High School Math : How to add and subtract integers in pre-algebra

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : How To Add And Subtract Integers In Pre Algebra

What is the difference between 8 and -2? 

Possible Answers:

-10

4

-6

10

6

Correct answer:

10

Explanation:

Since we want to find the difference between 8 and -2, we want to subtract -2 from 8. Since subtracting is equivalent to adding the same number with the opposite sign, we have the below:

\displaystyle 8 - (-2) = 8 + 2 = 10

 

 

Example Question #62 : High School Math

Find the difference. 

 

\displaystyle (-5) - 2 = 

Possible Answers:

\displaystyle -3

\displaystyle -7

\displaystyle 3

\displaystyle 10

\displaystyle 7

Correct answer:

\displaystyle -7

Explanation:

We are subtracting here, so it is important to remember that subtracting is really just adding the same number with opposite sign. Thus we can think of the problem as the following: 

\displaystyle (-5) + (-2), which we know is equal to \displaystyle -7.

Example Question #3 : How To Add And Subtract Integers In Pre Algebra

What is \displaystyle 10 - (-2) ? 

Possible Answers:

\displaystyle -12

\displaystyle -8

\displaystyle 12

\displaystyle 8

\displaystyle 14

Correct answer:

\displaystyle 12

Explanation:

Recall that subtracting integers is equivalent to adding the inverse. The inverse of a negative number is the positive number with the same magnitude.

Thus, our problem is equivalent to \displaystyle 10 + 2 = 12.

Example Question #4 : How To Add And Subtract Integers In Pre Algebra

Evaluate the following expression: 

\displaystyle -2 - (-4)

Possible Answers:

\displaystyle -6

\displaystyle 6

\displaystyle -2

\displaystyle 2

\displaystyle 8

Correct answer:

\displaystyle 2

Explanation:

Recall that subtracting is equivalent to adding the inverse:

\displaystyle -2 - (-4) = -2 + (-(-4))

The inverse of a negative number is a positive number:

\displaystyle -2 - (-4) = -2 + 4 = 2

Example Question #66 : High School Math

What is: 

\displaystyle -4 + 8

Possible Answers:

\displaystyle -4

\displaystyle 12

\displaystyle 4

\displaystyle -12

\displaystyle 16

Correct answer:

\displaystyle 4

Explanation:

Recall the placement of numbers on the number line. \displaystyle -4 is \displaystyle 4 spaces to the left of \displaystyle 0, and then we add \displaystyle 8, resulting in movement to the right. 

When we add these spaces we end up going \displaystyle 4 spaces back to \displaystyle 0 and then \displaystyle 4 additional spaces to end at \displaystyle 4

Example Question #5 : How To Add And Subtract Integers In Pre Algebra

What is \displaystyle 8 - (-3) ? 

Possible Answers:

\displaystyle 11

\displaystyle 33

\displaystyle -11

\displaystyle -5

\displaystyle 5

Correct answer:

\displaystyle 11

Explanation:

Recall that subtracting a negative number is equivalent to adding the opposite. Thus, \displaystyle 8 - (-3) = 8 + 3 = 11

Example Question #6 : How To Add And Subtract Integers In Pre Algebra

What is \displaystyle -3 - (-5)

Possible Answers:

\displaystyle 2

\displaystyle 8

\displaystyle 15

\displaystyle -8

\displaystyle -2

Correct answer:

\displaystyle 2

Explanation:

Recall that subtracting negative numbers is equivalent to adding the opposite. Then, we have that: 

\displaystyle -3 - (-5) = -3 + 5 = 2

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