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How do you take 15 away from 74 using a number line?
74 - 15 = ?
In this lesson you will learn how to solve subtraction
problems by using a number line.
Let’s Review number line samples
79 80 81 82 83 84 85 86 87 88 89 90
50 60 70 80 90 100 110 120 130 140 150 160
A Common Misunderstanding
Not paying attention to the scale on a given number line.
25 30 35 40 45 50 55 60 65 70 75 80
75 - 10 = 65
A Common Misunderstanding
Counting the unit marks and not the spaces when using a number line.
25 26 27 28 29 30 31 32 33 34 35 36
34 - 4 = 30
Core Lesson
74 - 15 = ?
74 - 15 = 59
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
Core Lesson
74 - 15 = ?
74 - 15 = 59
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
Think 75 - 15 = ?Remember to take one away later!
Core Lesson
To ride the roller coaster you must be 60 inches tall. Dana is 13 inches too short. How tall is she?
25 30 35 40 45 50 55 60 65 70 75 80
47
Think 60 - 13 = ?
60 - 13 = 47
Dana is 47 inches tall.
Core Lesson To ride the roller coaster you must be 60 inches tall. Dana is 13 inches too short. How
tall is she?
25 30 35 40 45 50 55 60 65 70 75 80
47
Think 60 - 15 = ?
60 - 13 = 47
Dana is 47 inches tall.
Remember to add 2
back later!
In this lesson you have learned how to solve subtraction
problems by using a number line.
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