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GRE Quant > Math tips and vocab > Flashcards

Math tips and vocab Flashcards

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1
Q

קודקוד של מצולע

A

vertex of square or rectangle

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2
Q

Quadrilateral

A

מצולע

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3
Q

מרובע חסום במעגל

A

Square ABCD is inscribed in circle O

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4
Q

מהירות בבעיית תנועה

A

Rate

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5
Q

1 pound

A

16 Ounces

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6
Q

Equilateral Triangle

A

משולש שווה צלעות

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7
Q

גובה של משולש

A

Altitude

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8
Q

Tangent

A

משיק

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9
Q

Consecutive positive even integers

A

2,4,6,8,10

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10
Q

1/8

A
  1. 5%

0. 125

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11
Q

1/6

A
  1. 6%

0. 165

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12
Q

1/3

A

33%

0.33

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13
Q

3/8

A
  1. 5%

0. 375

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14
Q

2/5

A

40%

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15
Q

5/8

A
  1. 5%

0. 625

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16
Q

2/3

A
  1. 6%

0. 6

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17
Q

3/4

A

75%

0.75

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18
Q

4/5

A

80%

0.8

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19
Q

5/6

A
  1. 3%

0. 83

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20
Q

7/8

A
  1. 5%

0. 875

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21
Q

משולש שווה שוקיים

A

Isoscles Triangle

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22
Q

משולש ישר זווית

A

Right triangle

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23
Q

3:4:5 Triangle

A

6:8:10

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24
Q

5:12:13

A

10:24:26

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25
Q

45•:45•:90•

A

1:1:_\2

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26
Q

30:60:90

A

1 :/ 3: 2

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27
Q

מטבע הוגן

מאוזן

A

Fair coin

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28
Q

Diameter

A

קוטר

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29
Q

קו ישר שמחבר שתי נקודות שנמצאות על היקף מעגל. הקוטר הוא הארוך מבין קוים אלה.

A

Chord AB connects points A B on the circumference.

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30
Q

Quantitative comparison tip

A

Make sure to simplify expressions all the way using the enequal sign.

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31
Q

Semicircle

A

חצי מעגל

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32
Q

Prime number facto tip

A

Always decompose numbers all the way down

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33
Q

Prime numbers

A

1 is not a prime number

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34
Q

Geometry tip

A

You can’t assume size according to diagram- unless it says so.

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35
Q

Data graph tip

A

If you misread the title of what the graph reads, you could get the question wrong. Read the titles carefully and linearly

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36
Q

Remainder tip

A

0 is a multiple of 7… or any other integer. So 3 is an integer- where if it is divided by 7 it leaves a remainder of 3.

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37
Q

LCM - Least common multiple

A

המספר הכי קטן שמתחלק בשני המספרים. 30 הינו הכפולה הקטנה ביותר של 6 ועשר.

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38
Q

GCD- Greatest common divisor.

GCF- Greatest common factor.

A

The largest integer that is a factor of two numbers.

המספר השלם הגדול ביותר שהוא גורם משותף של שני מספרים אחרים.

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39
Q

Rational number

A

Any number that can be expressed as a fraction

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40
Q

13 X 13

A

169

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41
Q

14 X 14

A

196

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42
Q

15 X 15

A

225

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43
Q

16 X 16

A

256

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44
Q

17 X 17

A

289

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45
Q

18 X 18

A

324

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46
Q

19 X 19

A

361

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47
Q

20 X 20

A

400

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48
Q

21 X 21

A

441

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49
Q

Stats tip for order of data

A

If they give you a set of data, make sure to organize it consecutively so that you can find the Md and the range…

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50
Q

Vertical Angles

A

זוויות קודקודיות

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51
Q

A line that bisects an angle

A

חוצה זווית לשתי זוויות שוות

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52
Q

Midpoint

A

נקודת האמצע על קו

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53
Q

Transversal

A

a line that intersects a pair of parallel lines- forming eight angles

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54
Q

Exterior Angle

A

זווית חיצונית למשולש

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55
Q

3 : 4 : 5 Triangle angles

A

a= 36.86 b = 53.13 c = 90

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56
Q

5 : 12 : 13 Triangle angles

A

a =

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57
Q

8 : 15 : 17 Right triangle

A

Remember length

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58
Q

7 : 24 : 25

A

Remember length

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59
Q

Sqrt (20)=Sqrt (4 X 5)

A

Sqrt (4) X Squrt (5)

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60
Q

Triangle Inequality

A

The sum of the lengths of any two sides of a triangle is greater than the length of the third side.

a < b+c

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61
Q

Triangle Inequality

A

The difference of the lengths of any two sides of a triangle is less than the length of the third side

A> |b - c|

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62
Q

Pentagon

A

five side Polygon

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63
Q

Hexagon

A

6 sides

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64
Q

Octagon

A

8 sides

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65
Q

Decagon

A

10 sides

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66
Q

The sum of the measures of the n angles in a polygon with n sides is

A

(n - 2) x 180

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67
Q

In any polygon, the sum of the exterior angles, taking one at each vertex

A

360

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68
Q

Regular polygon

A

מצולע משוכלל

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69
Q

In any regular polygon, the measure of each interior angle is

A

(n-2) x 180/ n

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70
Q

In any regular polygon, the measure of each exterior angle is

A

360/n

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71
Q

Parallelogram

A

מקבילית

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72
Q

Trepezoid

A

One pair of sides- parallel , and the other is not

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73
Q

Parallelogram area

A

A=bh

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74
Q

Trepezoid area

A

A=0.5 (b1+b2)h

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75
Q

Alternative square area formula

A

A=0.5d^2

Where d the length of the diagonal

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76
Q

Rectangle fact

A

For a given perimeter- the rectangle with the largest area; and smallest perimeter is a square

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77
Q

Arc

A

Two points on a circle and all points between them.

קשת

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78
Q

Central angle

A

Vertex is at the center of the circle

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79
Q

Inscribed in

A

חסום ב

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80
Q

Rectangular solid

A

Box

תיבה מלבנית

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81
Q

Faces

A

פאות

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82
Q

Edges

A

Sides of rectangle

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83
Q

1 yard

A

36 inches

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84
Q

1 yard

A

3 feet

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85
Q

1 foot

A

12 inches

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86
Q

Inequalities tip

A

Don’t forget to switch the direction of the unequal sign when dividing and multiplying by a negative number.

When being asked for an abstract problem- make sure they are not playing with direction switching

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87
Q

Fractions and Decimals tip

A

0.012 does not equal 0.1212 unless they say the word approximately

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88
Q

Word problem

A

Always write down and circle the variable you are trying to identify

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89
Q

Rate and distance tip

A

Average Rate (speed)= the total distance traveled divided by the total time spent traveling.

Not necessarily X+Y/2….
Average Speed = Total Distance/ Total Time .

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90
Q

Rate and distance tip

A

Don’t forget that when you are asked about time, and the q mentions slower- that means more seconds. And faster means less seconds…

Thus 5 seconds faster- means 5 seconds less….

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91
Q

Quartile tip

A

This is a GRE method- not the one learned in Israel.

A quartile is defined as the median of half of a set of data.
data.

For the first half, {2, 5, 7, 11, 16, 24}, the median is (7 + 11)/ 2 = 9 = Q1.

The first quartile (or Q1) of a set of data is the median of the lower half of the data. For the first half, {2, 5, 7, 11, 16, 24}, the median is (7 + 11)/ 2 = 9 = Q1.

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92
Q

Normal distribution

+1 sd

A

+1 SD= 34%

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93
Q

Normal distribution

+2 SD

A

+2 SD= 48%

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94
Q

Linear transformation on distribution

A

multiplying all numbers by a number will change the standard deviation

Sy= |a|*Sx

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95
Q

Markup

A

Markup is the difference between the cost of a good or service and its selling price.

A markup is added to the total cost incurred by the producer in order to produce a profit.

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96
Q

% tip

A

When working with %, always remember to relate the percent change to the original quantity.

That is- as the question what is the original quantity at a given time?
And then - what kind of percentage change would it need to be multiplied with in order to arrive at quantity 2.

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97
Q

Semantics regarding word problems

A

Notice the difference between “at least” and “greater than”.

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98
Q

Factoring tip

A

When finding the factors of two given numbers you need to look for all possible combinations

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99
Q

Tenths digit

A

ספרת העשיריות אשר מימין לנקודה

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100
Q

Tens digit

A

ספרת העשרות אשר משמאל לנקודה וגם משמאל לספרת האחדות

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101
Q

Polygon angle tip

A

Do not assume that a picture of a regular polygon is indeed in fact a regular polygon- they might be trying to trick you…

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102
Q

Hypotenuse

A

יתר

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103
Q

Triangle third side law

A

you can use both parts of the rule a+b>c and c>a-b…. to create a range

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104
Q

quadratic equation

A

משוואה ריבועית

aX^2+bX+c=0

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105
Q

x^a=x^b

A

a=b ; unless x=1

106
Q

a^2-b^2

A

(a+b)(a-b)

107
Q

quadratic equation

A

משוואה ריבועית

108
Q

x^a=x^b

A

a=b

109
Q

(X^a)(X^b)

A

X^a+b

110
Q

X^a/X^b

A

X^a-b= 1/X^b-a

111
Q

X^0

A

0; 0^0 is non-defined

112
Q

(X^a)(Y^a)

A

(XY)^a

113
Q

(X^a)^b

A

X^ab

114
Q

The quadratic formula

A

-b+-sqrt(b^2-4ac)/2a=x

115
Q

Solution set for inequality

A

defined as the set of all real numbers that can satisfy the inequality - apparent by solving the inequality.

116
Q

Simple interest

A

Based only on the initial deposit- called the principal

117
Q

Principal (of interest)

A

the amount on which interest is computed- for a given period of time

118
Q

Interest

A

earned on an investment over a specific time period

119
Q

Simple interest

A

Based only on the initial deposit- serves as the amount on which interest is computed

120
Q

V=P(1+rt/100)

A

The Value V at the end of t years equals the amount invested (P) x (1+rt/100). for a given interest of r %.

121
Q

Compound interest

A

in the case of compound- interest is added to the principal at regular time intervals. Each addition of interest is termed - compounded.

In an annual interest compounding.

V=p(1+r/100)^t

122
Q

Compound interest n times per year

A

V=P(1+r/100n)^nt

123
Q

(C G) Coordinate Geometry Symmetry

A

P 4 is the reflection P 1 about the X-axis= P 2 and P 1 are symmetric about the x-axis

P 2 is the same for the Y axis.

P 3 is the same for the origin.

124
Q

(C G) Coordinate geometry distance between two points

A

Use the pythagorian theorem
Construct a right triangle. Sometimes you can invent a point that is not even there to construct a right triangle.

Find the hypothenus- Yeter.

125
Q

(C G) Slope equation

A

Y2-Y1/X2-X1 Called rise over run

126
Q

(C G) Horizontal line coordinate geometry

A

y=b; While m=0

127
Q

(C G) Line equation

A

Y=mX+b

128
Q

(C G) Parallel lines

A

Have the same slopes- i.e. the slopes are equal.

129
Q

(C G) Perpendicular lines

A

Slopes are negative reciprocals of each other.

130
Q

(C G) Perpendicular of Y= 2X+5

A

Y= - 1/2X +b

131
Q

(C G) Intercept of X

A

Y=0

132
Q

(C G) Solution to a system of two linear equations of the form Y=mX+B

A

It is the point where the two lines intersect on the graph

133
Q

(C G) Solution to a system of two linear inequalities of the form: y=mx+b

A

Each point that satisfies an inequality is either on the line-or below/above it…

Therefore the graph might consist of the line and all of the area below it/above it.

Thus the solution of the system consists of all of the points that lie in the shaded region that is common to the two line boundaries.

134
Q

(C G) Y=X Symmetry

A

For any point (a,b), a point with interchanged coordinates (b,a) is a reflection of (a,b) about the line y=x;

In other words- (a,b) and (b,a) are symmetric about the line Y=X – this is true for any graph and for any point- about this special line.

135
Q

(C G) Interchanged Y and X

A

Interchanging Y and X in the equation of any line yields another graph that is the reflection of the original graph about the line y=x

136
Q

(C G) Parabola

A

Y = ax^2 + bx + c;
a, b, c are constants.
a =/o.

137
Q

(C G) X intercept of parabola

A

When- ax^2 + bx + c=0

138
Q

(C G) Vertex of parabola

A

Point of min or max. Determined by the value of a -+

139
Q

(C G) Parabola symmetry

A

Every parabola is symmetric with itself about the vertical line that passes through its vertex.

The two x-intercepts are equidistant from this line of symmetry.

140
Q

(C G) Parabola y coordinate

A

When x equals 0

141
Q

(C G) A graph of a circle

A

(x-a)^2+(y-b)^2 = r^2

Center of the circle is at point a,b – and the radius is r.

142
Q

(C G) h(x)= |x|

A

A piecewise-defined function:

h (x) = { x, x >=0 ; -X , X< =0}

143
Q

(C G) Shifting :The graph of h(x)+c

A

The graph of h(x) shifted upward by c units.

144
Q

(C G) h(x) - C

A

The graph of h(x) shifted downward by c units.

145
Q

(C G) the graph of h(x+c)

A

The graph of h(x) shifted to the left by c units

146
Q

(C G) The graph of h(x-c)

A

The graph of h (x) shifted to the right by c units.

147
Q

f(x)=2|x-1|

A

The graph of |X| shifted to the right by one unit and then stretched vertically away from the x axis by a factor of 2

148
Q

ch(x)

A

The graph of h(X) stretched vertically by a factor of c if c>1

149
Q

ch(x)

A

The graph of h(x) shrunk vertically by a factor of c if 0<1

150
Q

Congruent line segments

A

Line segments that have equal lengths

151
Q

Line segment

A

A part of a line that contains all points between two end points on the line- including the end points.

152
Q

Opposite angles = vertical angles

A

זוויות קודקודיות

153
Q

congruent angles

A

Angles that have equal measures

154
Q

Acute angle

A

has less than 90 degrees.

זווית חדה.

155
Q

Obtuse angle

A

זווית קהה

156
Q

Polygon

A

A closed figure formed by 3 or more line segments

157
Q

Side of polygon

A

פאות המצולע

158
Q

Vertices

A

קודקודי המצולע

End points of polygons where a side is joined by two other sides.

159
Q

Dividing polygons into triangles

A

Polygon with n sides can be divided into n-2 triangles

A pentagon can be divided into 3 triangles

160
Q

Sum of measures of the interior angles of a polygon

A

(n-2)(180)

161
Q

Legs of a right triangle

A

ניצבים

162
Q

congruent triangles

A

משולשים זהים

Have 3 identical sides.
or
Have 2 identical sides and identical included angle.
or
2 Identical angles and congruent included angle.

163
Q

Similar Triangles

A

have congruent angles.

And similar sides in terms of ratios.

164
Q

Triangle ABC and DEF are similar

A

AB/DE=BC/EF=AC/DF

165
Q

Sector of a cirle

A

Is a region bounded by an arc of the circle and two radii.

166
Q

Point of tangency

A

נקודת ההשקה

167
Q

Radios drawn to the tangent point

A

Forms a 90 degree angle with the tangent.

168
Q

A polygon is inscribed in a circle

A

A circle is circumscribed about the polygon

169
Q

Inscribed right triangle

A

Has one side as the diameter of the circle.

The hypothenus.

170
Q

A polygon is circumscribed about a circle.

A

If each side of the polygon is tangent to the circle.

Equivalently- the circle is inscribed inside a polygon.

171
Q

Two or more circles with the same center

A

are called concentric circles.

172
Q

Rectangular solid

A

תיבה
12 Edges.
8 vertices.

173
Q

Face of rectangular solid

A

פאות התיבה

174
Q

Edge of rectangular solid

A

Line segment that is the intersection of two faces.

175
Q

Vertex of rectangular solid

A

The point at which edges intersect.

176
Q

Volume of rectangular solid

A

V=lwh

177
Q

Surface area of rectangular solid

A

A=2(lw+lh+wh)

178
Q

Circular cylinder

A

Galil

It has an axis which is the line that connects the centers of the two bases.

179
Q

Right circular cylinder

A

The axis is perpendicular to the bases.

The length of the axis is the height of the cylinder.

180
Q

Volume of right rectangular cylinder

A

V= πr^2h

181
Q

Surface are of right rectangular cylinder

A

A=2(πr^2)+ 2πrh

182
Q

When working with a parrallelogram

A

Don’t assume that the diagonal creates a 90 degree angle with anything.

183
Q

Similar triangles

A

Remember to use similarity of sides as ratio equations- instead of taking longer routes such as the `pythagorean theorem.

184
Q

Similarity of triangles

A

Applies to the sides. But not necessarily to the area.
To compare the areas of two similar triangles, you need to breakdown the area equation of both triangles, and see how they compare.

185
Q

Parameter of triangle

A

Knowing only the parameter of a triangle is not enough to determine it’s minimal area. The maximal area can be determined using the equilateral, but the minimal area can be closed to 0 when the triangle is stretched all the way….

186
Q

Tip

A

Remember to divide by 2 when calculating triangle area

187
Q

Triangle tip

A

If you know that the sides of a triangle are for example 8, 15, 17… than you know it’s a right triangle without even knowing the angles. This is because of the ratios triangles have with their angles.

188
Q

Measures of central tendency

A

מדדי מרכז

189
Q

Measures of position

A

מדדי מיקום

190
Q

Measures of dispersion

A

מדדי פיזור

191
Q

Percentiles

A

There are 99 percentile numbers that divide the data into 100 roughly equal groups.

192
Q

Quartiles

A

(From L to Q1), (from Q1 to Md (Q2)), (from Md to Q3), (from Q3 to G).

193
Q

Quartiles 2

A

Q2=Md; Divides the data into two equal parts.
Q1 divides the lower part into to equal parts (The Md).
Q3 is the median of the greater group.

194
Q

Range

A

Difference between G and L. The greatest and the lowest respectively.

195
Q

Outliers

A

GRE uses the term outliers in the context of range of distribution.

196
Q

Interquartile range

A

Not affected by outliers.
Q3-Q1.
Measures the spread of the middle half of the data.

197
Q

Box-plot

A

Also called Box-and-whisker plot.
A plotting on the number line of: L, Q1, Q2, Q3, and G.
They show where the 4 quartile groups lie
The box can be used to identify each of two middle quartile groups of data, and “whiskers” extend from them to the extreme values.

They are useful for comparing two sets of data side by side.

198
Q

Standard Deviation

A

GRE algorithm:
1. Calculate the mean of n values.

  1. Find the difference between the mean and each of the n values.
  2. Squaring each of these differences.
  3. Finding the average of the n squared differences.
  4. Taking the non-negative squared root of the average squared differences.
199
Q

Sample standard deviation

A

Dividing the sum of the squared differences by (n-1) instead of n.

טעות התקן.

Different than-
population standard deviation.
Which is סטיית תקן

200
Q

Distances in SDs

Or standardization

A

A given point could have a distance from the mean by:

x-x’/sd….

Also creates the process of standardizing the data.
For each point it creates a measure of position relative to the rest of the data regardless of the variable and measuring units of that variable.

201
Q

Most of the data

A

In any group of data, most of the data are within about 3 SDs above or below the mean.

After standardizing the mean becomes 0 and a number line extending from -3 Z and +3Z

202
Q

Counting methods

A

Counting objects in probability theory

203
Q

Set

קבוצה

A

A collection of members or elements that have the same property.

Finite sets and infinite sets.

204
Q

Empty set

A

קבוצה ריקה

205
Q

Subset

A

{2,8} is a subset of {0,2,4,6,8}.

0/ is a subset of every set.

206
Q

A list

A

A set in which the members are ordered

207
Q

Element repetition in a list

A

repetition of elements in a list- does not add more elements in the set.

208
Q

The number of elements |S|

A

S={1,2,3,4,5} ; |S| = 5 ; |0/| = 0

209
Q

The intersection of S and T

A

The set of all elements that are in both S and T and is denoted by S ח T

210
Q

The union of S and T

A

S U T

211
Q

Disjoint sets

A

or mutually exclusive sets
S and T have no mutual elements
S ח T = 0/

212
Q

|AUB|

A

|A|+|B| - |A ח B|

213
Q

Multiplication principle

A

Choice 1: K ; Choice 2: M : K x M different possibilities

214
Q

Permutations

A

Each order of n objects is called a permutation

215
Q

N Factorial

A

!N עצרת

0!=1

216
Q

n!/(n-k)!

A

The number of ways to select and order k objects out n objects

The number of permutations of n objects taken k at a time

217
Q

Combinations

A

Selecting K objects without caring about orders.

Number of ways to select without order=

The number of ways to select with order
: by
The number of ways to order

218
Q

The numbers of N objects taken K at a time

A

n!/k!(n-k)!

Given a set S
The formula gives:
The number of subsets of S that consist of k elements.

219
Q

N choose 0

A

n!/0!n! = 1

the only subset of S with 0 elements is the empty set.

220
Q

Random experiment

A

The result is uncertain

221
Q

Sample space

A

The set of all possible outcomes for a random experiment.

222
Q

Event

A

A particular set of outcomes

223
Q

Random selection

A

Each of the events is equally likely to to be selected (occur)

224
Q

P(E)

A

The number of names in event E/The total number of possible outcomes in the experiment

225
Q

E ח F

A

The event that both E and F occur

226
Q

P(E) U P(F)

A

P(E) + P (F) - P (E ח F)

227
Q

P(E) ח P (F)= 0

A

The events are mutually exclusive

228
Q

Independent events

A

E and F are independent if the occurrence of one event doesn’t affect the occurrence of the other.

In which case P (E ח F)= P(E)*P(F)

229
Q

Non independent events

A

P (E ח F) =\ P (E) * P (F)

230
Q

A random variable

A

For a random variable that represents a randomly chosen value from a distribution of data, the probability distribution of the random variable is the same as the relative frequency distribution of the data.

The distribution can be represented by a histogram.

231
Q

The mean of a random variable X

A

The expected value

The sum of each value of X multiplied with its probablity

232
Q

Discrete random variables

A

Consist of discrete points on a number line

233
Q

In the histogram for a random variable

A

the area of each bar is proportional to the probability represented by the bar.

234
Q

Uniform distribution

A

One in which every outcome has the same probablity

235
Q

In a normal distribution- about 2/3 of the data

A

are located within 1 SD of the mean

236
Q

In a normal distribution almost all of the data is located

A

within 2 SD of the mean

237
Q

In a normal distribution M+2SD

A

34%+14%

238
Q

In a normal distribution M+3SD

A

34%+14%+2%

239
Q

Data entry tip

A

If the question says: “give your answer to the nearest .01”

You need to be extra careful

240
Q

Range of definition

A

Sometimes they might try to trick you with the range of definition of a function. You need to make sure the function is either specifically defined (i.e= x=/1) or define it yourself… especially if there is a division line. Don’t become too habituated.

241
Q

Sum of arithmetic sequence

A

n(a1+an)/2

242
Q

Arithmetic sequence term

A

an = a1 + (n-1)d

an = am+ (n-m)d

243
Q

Zero

A

Is an integer

244
Q

Coordinate geometry

A

Inequalities can be used for the area beneath or above a line. Then you can use these inequalities to check if any point satisfies the inequality to determine if it’s in the aforementioned area.

245
Q

Sets

A

It can be wise to solve set problems with Venn diagrams.

246
Q

Within 2 standard deviations of the mean

A

All numbers from -2SD till +2SD

247
Q

Drawn to scale

A

Even a coordinate geometry X and Y axes need to be proclaimed as drawn to scale.

248
Q

Range comparison tip

A

Be extra sure not to forget about >= . if something needs to be larger than something else… then it can’t be equal to something else

249
Q

Geometric Progression

A

a(n)= r * a(n-1)

a(n) = a1 * r ^ (n-1)

250
Q

Sum of Geometric progression

A

a1 * (1-r^n)/1-r

251
Q

0.17 Billion

A

170 Million

252
Q

0.17 Million

A

170,000

253
Q

Before you answer a question

A

Read it until the end one more time, to make sure what they want of you

254
Q

The word non-negative

A

Actually means positive or zero

255
Q

When evaluating quantitative comparison

A

Make sure to check between numbers which are positive and larger than the classic choice of 1 & 2.

Pick 6 & 8, or even larger numbers, just to make sure if anything changes. Do the same for negative numbers.

256
Q

When answering a multiple choice question

A

Look at all answer choices as sometimes there are different levels of perceived truth

257
Q

If they tell you in a question that one of the variables =/ 0

A

Be prepared to divide something by that element

258
Q

Classic combinatorics formula accounting for subgroups among which order does not matter

A

Total number of items!/FirstGroup! SecondGroup! ThirdG!etc

259
Q

Overlapping sets formula

A

Total = G1+G2-Both+Neither

260
Q

When you have marbles with different colours pulled out of a hat

A

Sometimes the order does not matter

261
Q

Nearest whole percent

A

They asked me for the nearest whole percent of 0.666
And I accidentally gave 66%/
It should have been 67%

262
Q

CG common mistake

A

I was looking at a point in the (-,-) quadrant of the graph. And failed to think about the fact that (c,d) are both negative- and so the larger absolute value makes a variable smaller in this case.

GRE Quant (2 decks)

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