Math Flashcards

1
Q

What five steps would you use to solve the problem below:

In a classroom, the ratio of boys to girls is 4:3. If there are 28 boys, how many girls are there?

A
  1. Write as equation: 4:3 = 28:x

2: Write as fractions: 4/3 = 28/x

3: Cross multiply: 4x = 84

  1. Divide 4 on both sides to find x: x = 21
  2. Solution: 21 girls
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2
Q

What five steps would you use to solve the problem below:

The ratio of apples to oranges in a basket is 3:2. If there are 30 fruits in total, how many apples and how many oranges are there?

A
  1. Write as equation: 3x + 2x = 30
  2. Add x’s: 5x = 30

3: Divide 5 on both sides to find x: x = 6

  1. Multiply the value of x to the ratios: 3(6); 2(6)
  2. Solution: apples = 18; oranges = 12
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3
Q

What six steps would you use to solve the problem below:

The product of two whole numbers is 36, and their ratio is 1:4. What is the smaller number of the ratio?

A
  1. Write as equation: 1x * 4x = 36
  2. Multiply x’s: 4x^2 = 36

3: Find the square root: 2x = 6

  1. Divide 2 on both sides to find x: x = 3
  2. Multiply the value of x to the ratios: 1(3); 4(3)
  3. Solution: 3:12; smallest number is 3.
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4
Q

What two steps would you use to solve the problem below:

A meter was cut at the 35-cm mark. What is the ratio of the smaller piece to the larger piece?

A
  1. Find the length of the other half: If a meter is 100 cm, then 35:65
  2. Simplify the ratio by dividing by 5: Answer = 7:13
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5
Q

What five steps would you use to solve the problem below:

If ₽75.00 is shared among three children in the ratio of 3:7:15. The size of the smallest share is?

A
  1. Write equation: 3x + 7x + 15x = 75
  2. Add the x’s: 25x = 75
  3. Divide 25 on both sides to find x: x = 3
  4. Multiply the value of x to the ratios = 3(3):7(3):15(3)
  5. Solution: Smallest share is 9
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6
Q

How do you know if a number is divisible by 2?

A

If it ends in 0,2,4,6, or 8.

Even numbers are usually divisible by 2.

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7
Q

How do you know if a number is divisible by 3?

A

If the sum of all digits is divisible by 3.

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8
Q

How do you know if a number is divisible by 4?

A

If the last two digits are divisible by 4

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9
Q

How do you know if a number is divisible by 5?

A

If the number ends in 0 or 5

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10
Q

How do you know if a number is divisible by 6?

A

If it is divisible by 2 and 3

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11
Q

How do you know if a number is divisible by 7?

A
  1. You multiply the last digit of the number by 2.

Ex: 252 = 2*2 = 4

  1. You subtract the result to the remaining digits.

Ex: 25-4 = 21

  1. If the end result is divisible by 7, then it is divisible by 7.

Ex: 21/7 = 3

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12
Q

How do you know if a number is divisible by 8?

A

If the number formed by the last 3 digits is divisible by 8.

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13
Q

If a number ends in 000, is it divisible by 8?

A

Yes.

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14
Q

How do you know if a number is divisible by 9?

A

If the sum of all digits is divisible by 9.

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15
Q

How do you know if a number is divisible by 11?

A

Three steps:

  1. Add all the numbers in the odd places.
  2. Add all the numbers in the even places.
  3. Subtract the results from Steps 1 and 2.

If the difference is divisible by 11, then it is divisible by 11.

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16
Q

How do you know if a number is divisible by 12?

A

If the number is divisible by both 3 and 4.

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17
Q

How do you add two numbers with different signs?

A

You subtract their base values then adopt the sign of the bigger number.

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18
Q

-8 + (+4) = -4

Why does the result adopt a negative sign?

A

Because the bigger number (8) uses a negative sign.

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19
Q

8 + (-4) = 4

Why does the result adopt a positive sign?

A

Because the bigger number (8) uses a positive sign.

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20
Q

When we simplify equation from -12 - (-7), to -12 + 7

Why does 7 eventually turn into a positive sign?

A

Because negative signs beside each other cancel each other out and turn positive.

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21
Q

How do you find the area of a square?

A

side^2

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22
Q

How do you find the area of a rectangle?

A

length * width

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23
Q

How do you find the area of a right triangle?

A

ab/2

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24
Q

How do you find the hypotenuse of a right triangle?

A

c^2 = a^2 + b^2

25
Q

How do you find the area of a circle?

A

Pi(r^2)

26
Q

How do you find the area of a parallelogram?

A

b*h

27
Q

How do you find the area of a trapezoid?

A

[(a+b)*h]/2

28
Q

What is the formula for simple interest (SI)?

A

(PRT)/100

P (Principal amount)
R (Rate of interest)
T (Time period, years)

29
Q

What is the formula for future value?

A

F = P + SI

30
Q

What is being asked in the problem below?

Vanille invested P5,000 in a certain business. How much will his money be in 2 years if it earns 12% interest in a year?

A

Future Value

31
Q

What is another term for Future Value?

A

Total Amount

32
Q

Rate of interest, when multiplying to the Principal Amount and Time, should be in decimal form.

True or False?

A

False. It should be taken as base value.

Ex: If R = 12%, it should be computed as 12 not .12

33
Q

Time period, when multiplying to the Principal Amount and Rate of interest, is always in years.

True or False?

A

True. If a given time period is in months, just divide it by 12.

Ex: 3 months (3/12 = 1/4 = .25 years)

34
Q

How do you convert a mixed fraction to an improper fraction?

For ex: 2 3/5 is?

A

Multiply the denominator to the whole number and add the product to the numerator.

2 3/5 = 13/5

35
Q

Convert .111111111 to a fraction

A

1/9

36
Q

(a+b)+c = a+(b+c) is what property?

A

Associative Property of Addition

37
Q

(ab)c = a(bc) is what property?

A

Associative Property of Multiplication

38
Q

a(b+c) is what property?

A

Distributive Property

39
Q

a+b = b+a is what property?

A

Commutative Property of Addition

40
Q

ab = ba is what property?

A

Commutative Property of Multiplication

41
Q

If given a set of scores, what formula do you use to find the RANGE?

A

Biggest Number - Smallest Number

42
Q

The equation of a line with equal coordinates is?

A

y = x

43
Q

A = 3x + 2y + 6xy is?

A

12 (no one knows why though)

44
Q

A = 3x + 2y is?

A

12 (no one knows why though)

45
Q

What is the formula of a slope?

A

Rise (X) over Run (Y)

46
Q

If a line is purely horizontal (aka only y), what is the value of its slope?

A

0

47
Q

If a line is purely vertical (aka only x), what is the value of its slope?

A

Undefined

48
Q

How many seconds are there in a 24 hour day?

A

86,400 seconds

49
Q

Given the algebraic term: 4xy

What is the numerical coefficient and what is the literal coefficient?

A

NC = 4
LC = xy

50
Q

What’s the different between Prime and Composite Numbers?

A

Prime numbers are numbers with only two factors: 1 and itself.

Composite numbers are natural numbers with factors more than 1 and itself.

51
Q

What are the formulas for discount rate and discounted price respectively

A

DR = Discount over original price

DP = Original price - Selling price

52
Q

Convert the following whole numbers into fractions: 2, 4, 6

A

4/2
16/4
36/6

53
Q

How do you find the perimeter of a shape?

A

Add all the sides BITCH!!!!

54
Q

What’s the difference between complementary and supplementary angles?

A

Complementary angles are two angles that add up to 90 degrees, while supplementary angles are two angles that add up to 180 degrees.

55
Q

What is the slope-intercept form?

A

line = slope + y-intercept

y = mx + b

56
Q

What formula do you use to find the interior angle of a polygon?

A

180*(number of sides - 2) all divided by number of sides

57
Q

What is the passing percentage if 83,152 examinees passed out of 228,963 in the LET?

A

36.32% (just memorize it)

58
Q

If a math problem in the LET, asks for a Toyota and Kia car, and these are the variables:

70 km, 2 hrs, 5 hrs

What answer should u remember?

A

50 kmph