use compatible number to estimate
problem:
1,212 + 347
537 + 3,244
329 + 64
To estimate the sum of these problems using compatible numbers, here's what you can do:
1. For the first problem, 1,212 + 347:
- Round 1,212 to the nearest hundred, which is 1,200.
- Round 347 to the nearest hundred, which is 300.
- Add the rounded numbers: 1,200 + 300 = 1,500.
- So, the estimated sum is 1,500.
2. For the second problem, 537 + 3,244:
- Round 537 to the nearest hundred, which is 500.
- Round 3,244 to the nearest hundred, which is 3,200.
- Add the rounded numbers: 500 + 3,200 = 3,700.
- So, the estimated sum is 3,700.
3. For the third problem, 329 + 64:
- Round 329 to the nearest ten, which is 330.
- Round 64 to the nearest ten, which is 60.
- Add the rounded numbers: 330 + 60 = 390.
- So, the estimated sum is 390.
By using compatible numbers and rounding, you can quickly estimate the sums of these problems.