Grade 4 Multiplication: Estimating Products

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   Estimate 922 × 4 by rounding 922 to the nearest hundred. What is your estimate?

   1. Round 922 to the nearest hundred: 922 → 900 (the tens digit is 2, so round down).
   2. Multiply the rounded numbers. 900 × 4: multiply 9 × 4 = 36, then put back the 2 zeros: 3600.
   3. So the estimate is about 3600.

   Answer: 3600

2. Example 2

   Estimate 4194 × 8 by rounding 4194 to the nearest thousand. What is your estimate?

   1. Round 4194 to the nearest thousand: 4194 → 4000 (the hundreds digit is 1, so round down).
   2. Multiply the rounded numbers. 4000 × 8: multiply 4 × 8 = 32, then put back the 3 zeros: 32000.
   3. So the estimate is about 32000.

   Answer: 32000

3. Example 3

   Estimate 59 × 3 by rounding 59 to the nearest ten. What is your estimate?

   1. Round 59 to the nearest ten: 59 → 60 (the ones digit is 9, so round up).
   2. Multiply the rounded numbers. 60 × 3: multiply 6 × 3 = 18, then put back the zero: 180.
   3. So the estimate is about 180.

   Answer: 180