Integer addition and subtraction: number line interpretation

The  exercise appears under the 7th grade (U.S.) Math Mission. This exercise to reinforce the understanding of the geometric and algebraic version of numbers.

Types of Problems
There is one type of problem in this exercise:


 * 1) Interpret the expression: This problem provides an arithmetic expression involving integers and either addition or subtraction. The student is expected to find the selection that correctly interprets the situation.Iaasnli1.png

Strategies
Knowledge of operations on positive and negative numbers and comfort with word problems are encouraged to ensure success on this exercise.
 * 1) A positive number is on the right and a negative is on the left.
 * 2) Adding is moving right and subtracting is moving left.
 * 3) A negative number can be thought of as "flipping over."

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) Many human calculators prefer geometric models of arithmetic to attain estimates efficiently.