CORE 131 Mathematics I Study Guide - Test

When multiplying decimals, do you always have to line up the decimals?

No

What is 1.23 x 4.56?

5.6088

What is -9.906 x -17.832 (Round to the nearest hundreth)

176.64

What is the absolute value of this number: -33

33

What is the absolute value of this number: 1,024

1,024

What is 5.89103 - 2.68?

3.21103

How would you write out this decimal? 1,956.381

one thousand nine hundred fifty-six and three hundred eighty-one thousandths

16.92

Sixteen and ninety-two hundreths

How would you write this decimal?

1,956.381

One thousand nine hundred fifty-six and three hundred eighty-one thousandths

Round this decimal to the tens place: 3.947613

3.9

Round this decimal to the hundredths place: 7.125852

7.13

Round this decimal to the thousandths place: 23.891246

23.891

Round this decimal to the ten thousandths place: 92.2147865

92.2148

Convert this percent to a decimal: 98.2%

0.982

Convert this decimal to a percent: 0.0954

9.54%

Convert this fraction to a percent, then to a decimal: 9/16

56.25

0.5625

What is the percent equation?

a = p * b

a = part of the whole

p = percent

b = whole

What is 38% of 126?

• 47.88

• Convert 38% into a decimal, then multiply it by 126.

a = p * b

a = 0.38 x 126

a = 47.88

36 is what percent of 94?

Round to the nearest hundredth

38.30%

Divide 36 by 94

a = p * b

36 = p * 94

36 = 94p

p = 0.38297 ← Write as a percentage!

6 is 20% of what number?

30

Convert 20% into a decimal, and then divide 6 by that decimal (0.20)

a = p * b

6 = 0.20 * b

6 = 0.20b

b = 30

Additive Inverse

The opposite of a number; adding both numbers together will get you zero.

What do these bars stand for? | |

Absolute Value

What is the additive inverse of this number: 99

-99

True or False?

| -38 | > | 9 |

True

True or False?

| -106 | < | 97 |

False

Calculate this expression

9 - (-18) + (-6)

21

Calculate this expression

-36/-6

6

True or False? These fractions are equivalent: 3/4 and 27/36

True

What value of x would make these fractions equivalent: 5/6 and x/30

25

What is this fraction reduced in its lowest terms: 99/33

3/1 (3)

Subtract these fractions. Write in lowest terms: 8/9-1/3

5/9

Multiply these fractions and reduce to lowest terms: 10/12 x 2/8

5/24

Subtract these fractions. Write in lowest terms: 1/9-3/7

-20/63

Divide these fractions and reduce to lowest terms: -12/16 ÷ 4/8

-3/2

Convert this mixed number into an improper fraction: 19/7

2 and 5/7

Convert this improper fraction into a mixed number: 3 and 9/18

63/18

What property is this: 7 + 3 = 3 + 7

Commutative Property of Addition

What property is this: 9 + (-9) = 0

Inverse Property of Addition

Convert this mixed number into an improper fraction: 2 ¼

9/4

What property is this: 21 x 1 = 21

Identity Property of Multiplication

What property is this:

(3x3) x 6 = 6 x (3x3)

Commutative Property of Multiplication

What property is this: (7+8) + 9 = 9 + (7+8)

Commutative Property of Addition

What property is this:

(9+7) + 21 = (21+7) + 9

Associative Property of Addition

What property is this:

(10x4) x 5 = (10x5) x 4

Associative Property of Multiplication

Write the literal equation for this statement: A number decreased by 7

x - 7

Write the literal equation for this statement: 8 more than a number

x + 8 or 8 + x

Write the literal equation for this statement: The product of 20 less than a number and 14 more than a number

(x-20)(x+14)

Write the literal equation for this statement: The quotient of a number and 16

x ÷ 16

Is this an identity equation?

6x - 24 = 6(x-4)

Yes. After solving, you get x = x. Therefore, any value of x would make this equation true, and its solution is all real numbers. (−∞,∞)

Is this an identity equation?

7x - 3 = 2x + 9

No. After solving, you get x = 2.4. Since x has one solution, it is not an identity equation.

What is the solution to this equation:

9x - 9 = 3x + 27

x = 6

What is the solution to this equation:

-12x -10 = 4x + 24

Round to the nearest hundreth

x = -2.13

Solve this equation for P:

Q = rP/36

P = 36Q/r

Use these formulas to convert -18 degrees Celsius to Fahrenheit.

°F = 9/5C + 32

°C = 5/9(F-32)

-2/5°F = -0.4°F

Write the ratio in its lowest terms:

20 miles to 80 miles

1/4

Write the ratio in its lowest terms:

12 days to 96 hours

3/1 (3)

Ratio

A comparison of two quantities

Which of the following qualifies as the ratio of x to y?