Identifying Strategies for Multi-Digit Addition
Strategy # 1: Counting up
27 + 4 = 31
Counting up is useful when one of the numbers that you want to add is small, like 4.
Using 100 as an Anchor for addition
Strategy #2: Using 100 as an Anchor
The Spanish club is planning a weekend trip. Each student will need to pay $36 for transportation and $98 for food and lodging. What is the total cost per student?
36
- 98
Estimate
- 100
140
Write the problem horizontally.
36 + 98
98 is close to 100. Find a way to make 100.
Break 36 into 34 + 2.
34 + 2 + 98
34 + 100 = 134
Therefore, the total cost per student is $134.
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