8th Grade Math Practice Quiz

1. What is (+8)x(-13)?

(+5)

(-100)

(-104)

(-900)

The correct answer is (-104) because when you multiply a positive number by a negative number, the result is always negative. Therefore, (+8)x(-13) equals -104.

Explanation

The correct answer is (-104) because when you multiply a positive number by a negative number, the result is always negative. Therefore, (+8)x(-13) equals -104.

2. What is 45% of $360.00?

$45.00

$162.00

$125.00

$350.00

To find 45% of $360.00, you can multiply $360.00 by 0.45. This will give you the amount of $162.00.

Explanation

To find 45% of $360.00, you can multiply $360.00 by 0.45. This will give you the amount of $162.00.

3. Which of the following is not a type of graph?

Pictograph

Bar graph

Line graph

External graph

Double bar graph

The options given are all types of graphs except for "external graph." This suggests that "external graph" is not a recognized type of graph.

Explanation

The options given are all types of graphs except for "external graph." This suggests that "external graph" is not a recognized type of graph.

4. What is the surface area of a cylinder?

LxW

2x(3.14x r)+(3.14x d x h)

Bxh/2

S2

LxWxH

The formula for the surface area of a cylinder is 2πr^2 + 2πrh. In the given answer, 2(3.14r) represents the area of the two circular bases of the cylinder, and (3.14dh) represents the area of the curved surface. Therefore, the given answer correctly calculates the surface area of a cylinder.

Explanation

The formula for the surface area of a cylinder is 2πr^2 + 2πrh. In the given answer, 2(3.14r) represents the area of the two circular bases of the cylinder, and (3.14dh) represents the area of the curved surface. Therefore, the given answer correctly calculates the surface area of a cylinder.

5. What is 3/4 divided by 3/8? (The lowest terms)

3/16

2

4/2

2/1

When dividing fractions, you can multiply the first fraction by the reciprocal of the second fraction. In this case, 3/4 divided by 3/8 is equal to (3/4) * (8/3). Simplifying this expression gives us (3 * 8) / (4 * 3), which is equal to 24/12. Further simplifying by dividing both the numerator and denominator by 12, we get 2/1. Therefore, the answer is 2.

Explanation

When dividing fractions, you can multiply the first fraction by the reciprocal of the second fraction. In this case, 3/4 divided by 3/8 is equal to (3/4) * (8/3). Simplifying this expression gives us (3 * 8) / (4 * 3), which is equal to 24/12. Further simplifying by dividing both the numerator and denominator by 12, we get 2/1. Therefore, the answer is 2.

6. What is the equivalent ratio to the unit rate of $6.00/14 mL?

6:14

1:7

3:7

7:6

The equivalent ratio to the unit rate of $6.00/14 mL is 3:7. This means that for every 3 dollars, there are 7 milliliters.

Explanation

The equivalent ratio to the unit rate of $6.00/14 mL is 3:7. This means that for every 3 dollars, there are 7 milliliters.

7. What is y equal to using: x/5+(-13)=y when x= 8

Y= -11.4

Y=12

Y=11.4

Y=8

By substituting x=8 into the equation x/5 + (-13) = y, we can solve for y. Plugging in the value, we get 8/5 + (-13) = y. Simplifying this expression, we have 1.6 - 13 = y, which gives us -11.4 = y. Therefore, y is equal to -11.4.

Explanation

By substituting x=8 into the equation x/5 + (-13) = y, we can solve for y. Plugging in the value, we get 8/5 + (-13) = y. Simplifying this expression, we have 1.6 - 13 = y, which gives us -11.4 = y. Therefore, y is equal to -11.4.

8. Find the following value using opposite operations.

r/10+3= 13

R=1000

R=10

R=100

R=13

To find the value of r, we need to reverse the operations in the equation. The equation states that r divided by 10, and then added by 3 is equal to 13. To reverse this, we subtract 3 from 13, which gives us 10. Then, we multiply 10 by 10 to get the value of r, which is 100. Hence, the correct answer is r=100.

Explanation

To find the value of r, we need to reverse the operations in the equation. The equation states that r divided by 10, and then added by 3 is equal to 13. To reverse this, we subtract 3 from 13, which gives us 10. Then, we multiply 10 by 10 to get the value of r, which is 100. Hence, the correct answer is r=100.

9. What is the length of side "c" if the sides of "a" is 20m and side "b" is 35m? (Hint: use a2+b2, then find the square root)

2098m

55m

1625m

40.3m

Explanation

10. What is the volume of a prism?

BxH

LxW

LxWxH

AxP

The volume of a prism is calculated by multiplying the base area (B) of the prism by its height (H). This is because the volume of a prism represents the amount of space it occupies in three dimensions. By multiplying the base area by the height, we are essentially finding the volume of the prism by multiplying the area of the base by the distance it extends in the vertical direction.

Explanation

The volume of a prism is calculated by multiplying the base area (B) of the prism by its height (H). This is because the volume of a prism represents the amount of space it occupies in three dimensions. By multiplying the base area by the height, we are essentially finding the volume of the prism by multiplying the area of the base by the distance it extends in the vertical direction.