We can solve 75 + 29 in a different way. The number 29 is one less than 30.
2
We can use a number line to find 75 + 30 and then make the answer one less because we have added one too much. So, 75 + 29 = 104.
+30
–1
104 105
75
3 We can also use number facts to help solve subtraction problems. 102 − 45 112 − 19 80 − 50
4 We can solve 112 − 19 in a different way.
The number 19 is one less than 20. We can use a number line to find 112 − 20 and then make the answer one more because we have subtracted one too much. So, 112 − 19 = 93
–20
+1
92 93
112
1 Try these additions. What strategy will you use each time? (a) 36 + 37 (b) 89 + 24 (c) 80 + 90 (d) 65 + 29 (e) 54 + 35
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