In this Grade 7 lesson from enVision Mathematics Chapter 1, students learn how to subtract integers by applying the additive inverse property, rewriting subtraction expressions such as a − b as equivalent addition expressions a + (−b). The lesson covers subtracting positive integers, integers with different signs, and negative integers, using number lines to model each case. Real-world contexts like football yardage and temperature changes help students connect integer subtraction to practical problem-solving.
Section 1
Applying the Rule for Subtracting Integers
Apply the rule that subtraction of integers is equivalent to adding the opposite: . This allows any integer subtraction problem to be solved using addition rules, including cases with negative integers where .
Section 2
Subtracting Integers on a Number Line
To model the subtraction problem on a number line, start at the point representing the first integer, . Then, move a distance of units. Move to the left if is positive, and move to the right if is negative.
A number line provides a visual way to understand integer subtraction. You always begin at the first number in the expression. Subtracting a positive integer is like a decrease, so you move to the left. Subtracting a negative integer is equivalent to adding its positive opposite, so you move to the right. The final position on the number line represents the answer to the subtraction problem.
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Section 1
Applying the Rule for Subtracting Integers
Apply the rule that subtraction of integers is equivalent to adding the opposite: . This allows any integer subtraction problem to be solved using addition rules, including cases with negative integers where .
Section 2
Subtracting Integers on a Number Line
To model the subtraction problem on a number line, start at the point representing the first integer, . Then, move a distance of units. Move to the left if is positive, and move to the right if is negative.
A number line provides a visual way to understand integer subtraction. You always begin at the first number in the expression. Subtracting a positive integer is like a decrease, so you move to the left. Subtracting a negative integer is equivalent to adding its positive opposite, so you move to the right. The final position on the number line represents the answer to the subtraction problem.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter