Negative number addition and subtraction: interpretation problems

The  exercise appears under the 7th grade (U.S.) Math Mission. This exercise helps understand the interpretation of positive and negative numbers in real-life situations.

Types of Problems
There are three types of problems in this exercise:


 * 1) Can it or can it not be represented: This problem provides an arithmetic expression with integers and some possible interpretations. The student is asked which situations can be represent by the expression and which cannot.Nnaasip1.png
 * 2) Which expression represents: This problem provides a real-life situation. The student is asked to select which of the expressions (if any) represents the situation.Nnaasip2.png
 * 3) Determine which are correct interpretations: This problem presents a context-driven situation. The student is asked which of a list of possibilities can represent the situation that is described in the problem.Nnaasip3.png

Strategies
Knowledge of operations on negative numbers and comfort with word problems are encouraged to ensure success on this exercise.
 * 1) Solving the problem first and then seeing which selections are correct (working backwards) can help to perform this problem efficiently.

Real-life Applications

 * 1) Familiarity with operations on integers will lead into comfort with other more advanced numbers, such as radicals, fractions and even imaginary numbers.
 * 2) Some of the problems in this exercise are real-life applications.