Rounding
Round to the nearest hundred.
654
700
6 x 40 =
240
6 x 125 =
6 x 100 = 600
First estimate. Then decide if the estimate is greater or less than the actual answer.
4 x 278
4 x 300 = 1,200
The estimate is greater than the actual answer.
Sam estimates the product of 211 and 6 is 1,800. Is that estimate reasonable?
No, the real estimate should be 1,200 because 211 rounds to 200. 200 x 6 = 1,200
Round to the nearest thousand.
7,964
8,000
700 x 3 =
2,100
7 x 486
7 x 500 = 3,500
First estimate. Then decide if the estimate is greater or less than the actual answer.
9 x 4,720
9 x 5,000 = 45,000
The estimate is greater than the actual answer.
Use estimation to check if the product is reasonable. Billy gets a product of 11,540 for 2,855 x 4. Is that answer reasonable?
Yes, because 3,000 x 4 = 12,000 which is close to 11,540.
Round to the nearest ten.
96
100
5 x 600 =
3,000
9 x 92
9 x 90 = 810
First estimate. Then decide if the estimate is greater or less than the actual answer.
3 x 8,230 =
3 x 8,000 = 24,000
The estimate is less than the actual answer.
Use estimation to check if the product is reasonable. Tammy gets a product of 1,645 for 211 x 5. Is that answer reasonable?
No, because 200 x 5 = 1,000, and that is not close to 1,645.
Round to the nearest hundred.
421
400
9 x 4,000 =
36,000
5 x 3,240 =
5 x 3,000 = 15,000
First estimate. Then decide if the estimate is greater or less than the actual answer.
8 x 23 =
8 x 20 = 160
The estimate is less than the actual answer.
Use estimation to check if the product is reasonable. Mary gets a product of 925 for 5 x 185. Is that answer reasonable?
Yes, because 5 x 200 =1,000, and that is close to 925.
Round to the nearest thousand.
5,876
6,000
6,000 x 3 =
18,000
5,588 x 4 =
6,000 x 4 = 24,000
First estimate. Then decide if the estimate is greater or less than the actual answer.
3 x 1,675 =
3 x 2,000 = 6,000
The estimate is greater than the actual answer.
Use estimation to check if the product is reasonable. Mark gets a product of 20,565 for 6,855 x 3. Is that answer reasonable?
Yes, because 7,000 x 3 = 21,000 which is close to 20,565.