Basic rules

Question 1

Strategy for solving an absolute value equation

Answer 1

Solve once for the positive value, then again for the negative. You get two answers.

Question 2

Algebraic inequality with negatives: don’t forget to do this

Answer 2

When multiplying or dividing by a negative, flip the sign

Question 3

Formula for overlapping sets

Answer 3

Total = Group 1 + Group 2 - Both + Neither

Question 4

Order of ops

Answer 4

PEMDAS: 
parentheses
exponents
multiply and divide
add and subtract

Question 5

FOIL method

Answer 5

When multiplying algebraic terms in parentheses, multiply the First, Outside, Inside, then Last terms.

Question 6

When multiplying two exponents with the same base…

Answer 6

Add the powers

Question 7

When dividing two exponents with the same base…

Answer 7

Subtract the powers

Question 8

When raising an exponent to another power…

Answer 8

Multiply the exponents

Question 9

Simplifying a negative exponent

Answer 9

Reciprocate: 5^-9 = 1/5^9

Question 10

Dividing fractions

Answer 10

Multiply by the reciprocal (flip denominator upside-down and multiply)

Question 11

An odd number to any power is…

Answer 11

odd

Question 12

Combinatorics when order matters

E.g. How many ways can 3 medals be awarded to 7 competitors?

Answer 12

(Pool!)/(Out!)

E.g. the number of options factorial over the number of unchosen options factorial

Question 13

Combinatorics when order doesn’t matter

E.g. How many teams of 3 can be picked from 7 people?

Answer 13

(Pool!)/(In!)(Out!)

Question 14

% of values within 1 SD of the mean

Answer 14

68%

Question 15

% of values within 2 SD of the mean

Answer 15

95%

Question 16

% of values within 3 SD of the mean

Answer 16

99.7%

Question 17

area of triangle

Answer 17

0.5 x base x height

Question 18

similar triangles

Answer 18

have the same angles, and the sides are proportionate

Question 19

The third side of a triangle…

Answer 19

Is greater than the difference of the other two sides, but less than their sum.

Question 20

Pythagorean theorem

Answer 20

a^2 + b^2 = c^2

Question 21

Isosceles triangle

Answer 21

two equal sides

Question 22

equilateral triangle

Answer 22

3 equal sides, all angles are 60°

Question 23

area of a parallelogram

Answer 23

base x height

Question 24

sum of angles in a polygon

Answer 24

180(n-2)

n = number of sides

Question 25

volume of cylinder

Answer 25

πr^2 x height

Question 26

surface area of cylinder

Answer 26

2πr^2 + 2πrh

Question 27

circumference of circle

Answer 27

πd
or
2πr

Question 28

area of circle

Answer 28

πr^2

Question 29

If one side of an inscribed triangle is the diameter of a circle…

Answer 29

the opposite angle is 90°

Question 30

sector area in a circle

Answer 30

proportionate to angle size: how much is the angle out of 180°? The sector is that much of the total area

Question 31

When a line intersects two other, parallel lines…

Answer 31

The corresponding angles are equal

Question 32

When two lines intersect, what do you know about their angles?

Answer 32

Opposite angles are equal

Question 33

Calculate slope of a line from two points

Answer 33

slope = rise/run = (y2 - y1)/(x2 - x1)

Question 34

midpoint between two points on a line in the coordinate plane

Answer 34

((x1 + x2)/2) , ((y1 + y2)/2)

Question 35

distance between two points in the coordinate plane

Answer 35

sq((x2 - x1)^2 + (y2 - y1)^2))