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Subtracting Integers on a Number Line. How to subtract using a number line. Place a circle on the number line to represent the first number in the problem. Since this is subtraction, the second number will tell you how much to take away. This is the opposite of addition.
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How to subtract using a number line • Place a circle on the number line to represent the first number in the problem. • Since this is subtraction, the second number will tell you how much to take away. • This is the opposite of addition. • A positive second number means you should move to the left. • A negative second number means you should move to the right. • The number you end on is the answer.
Example 1 • Model 5 - 4 using a number line. • Start at 5 on the number line. • Take away 4, or move 4 spaces to the left since the second number is positive. – 4 5 - 4 = 1
Example 2 • Model 5 – 8 • Start at 5 on a number line. • Take away 8, or move 8 spaces to the left since the second number is positive. – 8 5 - 8 = -3
Example 3 • Model 5 – (-4) • Start at 5 on the number line. • Take away -4, or move 4 spaces to the right since the second number is negative. – (-4) 5 – (-4) = 9
Example 4 • Model -3 - 4 on a number line. – 4 -3 - 4 = -7
Example 5 • Model -1 - (-6) on a number line – (-6) -1 – (-6) = 5
Example 6 • Model 4 - 10 on a number line – 10 4 - 10 = -6
Example 7 • Model -8 - (-12) on a number line – (-12) -8 – (-12) = 4
Example 8 • Model -2 - 6 on a number line – 6 -2 - 6 = -8
Example 9 • Model 3 - (-4) on a number line – (-4) 3 – (-4) = 7
Example 10 • Model -7 – (-7) on a number line – (-7) -7 – (-7) = 0