Worked examples
Two examples
Example 1
Estimate by rounding each number to the nearest whole number first: 7.8 × 3.2
- 7.8 rounds to 8, and 3.2 rounds to 3.
- 8 × 3 = 24.
Answer: 24
Example 2
Estimate by rounding each number to the nearest whole number first: 19.6 − 4.3
- 19.6 rounds to 20, and 4.3 rounds to 4.
- 20 − 4 = 16.
Answer: 16
Where this is taught: Quiz 14: Adding and Subtracting Decimals, “The guard is on duty, and this is its best shift”
The drill
Ten problems
This drill also has challenge problems. They use the same skill, set up the way the GED test sometimes sets up a problem, so that it looks new at first.
How many:
Type each answer, then press Check my answers at the bottom. Commas in large numbers are fine.Write each answer on the line. The answer key, with the reasoning, is on the last page.