Age Level: Grade 6
Learning Objectives: Understand that integers on a number line may be less than zero; demonstrate how negative integers are created by subtracting a larger number from a smaller number, or by multiplying or dividing a negative number with a positive number.
Experts in the field of education, as well as common core standards, state that students should be introduced to negative numbers in the sixth grade (Ryan). By this time, they should have a thorough understanding of the positive number line, how numbers change when added, subtracted, multiplied, or divided with each other. Once they comprehend this, they may be introduced to numbers less than zero, a more abstract concept. With standards in some states becoming stricter, this skill may soon be taught in fifth grade (Ryan).
Whether they realize it or not, most children do have experience with negative numbers. One excellent way to introduce your students to the idea of negative numbers is using the thermometer. Children living in colder climates will recognize the idea of negative temperatures, and based on experience they will understand that a temperature below zero is colder than zero, and thus lower. The thermometer on the right clearly shows temperatures above and below zero.
You are running the apple stand at the farmer’s market, and you have 5 apples left. Mrs. Johnson comes to the stand, and says she wants to buy seven apples. How many more apples would you need to give Mrs. Johnson all the apples she wants?
Mathematically, this story has the following formula: 5 - 7 = -2
You have five apples, but Mrs. Johnson wants to take away 7. This means that you are two apples short for Mrs. Johnson.
We may begin the illustration of this problem using a number line. Create a number line using the playing cards numbered -5 through 5, using the back of a card for zero (there are no zero cards in the deck). Alternatively, you may ask the student to draw the number line on paper.
We may present students with equations using the cards, as well as presenting them with possible answers. For example, we may present the equations 3 x -2 = ? or -8 ÷ 4 = ?.
Ryan, A.J. “When do kids learn negative numbers?” Global Post. http://everydaylife.globalpost.com/kids-learn-negative-numbers-3458.html