Integer addition and subtraction: find the missing value

The  exercise appears under the 7th grade (U.S.) Math Mission. This exercise practices finding the missing value in addition and subtraction problems.

Types of Problems
There is one type of problem in this exercise:
 * 1) Find the missing value: This problem shows an equation with a missing value. The student has to find the missing value.

Strategies
Knowledge of negative numbers and solving equations are essential to ensure success in this exercise.
 * 1) Number lines are useful for adding and subtracting negative numbers.