Estimating products by rounding off factors to the nearest ten
Group Activity 3
Estimate the product of 176 and 42 by rounding off the factors to thenearest ten.
In groups of three:
- Round off each factor to the nearest ten.
- Find the product of the rounded off numbers.
- Discuss the results with other groups.
Example 4
Estimate the product of 284 and 36 by first rounding off the factors to the nearest ten.
- 284 rounded off to the nearest ten is 280.
- 36 rounded off the nearest ten is 40.
- Estimate product is 280 × 40 = 11 200.
Exercise D
89 × 25 = | 169 × 7 = |
74 × 38 = | 387 × 9 = |
83 × 71 = | 8 × 463 = |
D2
Work out the following by rounding off each factor to the nearest ten:
- 275 × 16
- 326 × 39
- 754 × 47
- 384 × 55
- 555 × 28
- 293 × 46
276 rounded off to the nearest ten is .
12 rounded off the nearest ten is .
Estimated total number of eggs is .