Math 1 PreTest

1. What is the absolute value of 21?

21

-21

The absolute value means the distance from zero. Distance can never be negative, so the answer must be positive.

Explanation

The absolute value means the distance from zero. Distance can never be negative, so the answer must be positive.

2. Solve 10 = 2x + 4.

X = 3

X = 7

X = 4

X = 12

This is a two step equation. You first must subtract 4 from each side to get 2x by itself. Then you must divide each side by 2 to get x by itself.

Explanation

This is a two step equation. You first must subtract 4 from each side to get 2x by itself. Then you must divide each side by 2 to get x by itself.

3. Decide which expression represents the following statement: Five less than twice a number.

2x + 5

5x - 2

5x + 2

2x - 5

Twice a number is 2x. But you also need five less than that, which means you need to subtract five from 2x.

Explanation

Twice a number is 2x. But you also need five less than that, which means you need to subtract five from 2x.

4. Solve the equation: x - 15 = 12

X = 3

X = 27

X = - 3

X = -27

You must add 15 to both sides to get x by itself.

Explanation

You must add 15 to both sides to get x by itself.

5. Evaluate: (-12) + 10

22

-2

-22

2

If an object is 12 feet below sea level (-12) and then it goes up 10 ft (+ 10) the object is still 2 feet below sea level (-2).

Explanation

If an object is 12 feet below sea level (-12) and then it goes up 10 ft (+ 10) the object is still 2 feet below sea level (-2).

6. Add the following 2/3 and 4/5.

22/15

6/8

29/15

6/15

You must find a common denominator when adding and subtracting fractions. The smallest number that both 3 and 15 will go into is 15. Therefore the common denominator is 15. You then must multiply 2 by 5, because that is what you had to multiply 3 by to get 15. Then you must multiply 4 by 3 because that is what you had to multiply 5 by to get 15. You now have the fractions 10/15 and 12/15. When adding fractions, the denominator stays the same and you add the numerators. Therefore, the answer is 22/15, which does not reduce.

Explanation

You must find a common denominator when adding and subtracting fractions. The smallest number that both 3 and 15 will go into is 15. Therefore the common denominator is 15. You then must multiply 2 by 5, because that is what you had to multiply 3 by to get 15. Then you must multiply 4 by 3 because that is what you had to multiply 5 by to get 15. You now have the fractions 10/15 and 12/15. When adding fractions, the denominator stays the same and you add the numerators. Therefore, the answer is 22/15, which does not reduce.

7. Apply the distributive property to 2(x + 1).

X + 2

2x + 2

2x + 1

2x + 3

The distributive property means to multiply each value in the parenthesis by the value outside.

Explanation

The distributive property means to multiply each value in the parenthesis by the value outside.

8. Which of the following is a perfect square?

6

12

25

32

A perfect square is a number which represents the multiple of the same two numbers. For example 9 is perfect square because it represents 3 times 3. In this case the only number that represents a a multiple of the same two numbers is 25, which is 5 times 5.

Explanation

A perfect square is a number which represents the multiple of the same two numbers. For example 9 is perfect square because it represents 3 times 3. In this case the only number that represents a a multiple of the same two numbers is 25, which is 5 times 5.

9. Which of the following is the correct volume for a cube which has sides that measure 3in?

6

9

15

27

To find the volume of a cube you must multiply the length, the width and the depth. In a cube all three of these are the same length, so you must multiply 3 by 3 by 3.

Explanation

To find the volume of a cube you must multiply the length, the width and the depth. In a cube all three of these are the same length, so you must multiply 3 by 3 by 3.

10. What is the slope of the line with equation y = 3x - 10.

-10

10

3

-3

Slope intercept form of a line is y = mx + b, where m is the slope and b is the y-intercept. 3 is the slope of this line.

Explanation

Slope intercept form of a line is y = mx + b, where m is the slope and b is the y-intercept. 3 is the slope of this line.

11. Find the median of the following data:

3, 1, 7, 6, 11, 2, 4, 13, 5

5

5.8

5.5

6

The median is the value that splits a data set in half. However, before you can find the median, you must order the data from least to greatest.

Explanation

The median is the value that splits a data set in half. However, before you can find the median, you must order the data from least to greatest.

12. What is the LCM of 6 and 15?

6

30

3

2

LCM means least common multiple. You want to find the smallest number that goes into both numbers.

Explanation

LCM means least common multiple. You want to find the smallest number that goes into both numbers.

13. Use the Pythagorean Theorem to find the hypotenuse of a right triangle with legs that measure 3 and 4.

25

7

5

49

Pythagorean theorem states that the sum of the squares of the two legs of a right triangle is equal to the square of the hypotenuse. Therefore in this case 9 + 16 should be equal to the square of the unknown hypotenuse. So 25 is the square of the hypotenuse. But you must take the square root of 25 to find the actual length, which is 5.

Explanation

Pythagorean theorem states that the sum of the squares of the two legs of a right triangle is equal to the square of the hypotenuse. Therefore in this case 9 + 16 should be equal to the square of the unknown hypotenuse. So 25 is the square of the hypotenuse. But you must take the square root of 25 to find the actual length, which is 5.

Math 1 Pretest