Estimate sensible totals and choose calculations that match practical situations.
Example 1
There are 216 people at a fair. 83 more arrive, then 74 leave. How many people remain?
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Answer: 225
- Arriving adds people: 216+83=299.
- Leaving subtracts people: 299−74=225 people.
Example 2
There are 149 people at a fair. 89 more arrive, then 37 leave. How many people remain?
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Answer: 201
- Arriving adds people: 149+89=238.
- Leaving subtracts people: 238−37=201 people.
Example 3
A school counted 426 hats and 106 caps. Round each count to the nearest hundred, then estimate the total.
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Answer: 500
- 426 rounds to 400; 106 rounds to 100.
- Add the rounded counts: about 500 hats and caps.