Estimating Differences
Materials: numeral cards (0-9)
______________________________________________________________________________- Turn over six cards to make two 3-digit numbers.
- Estimate the difference between the two numbers by rounding each
number to the nearest hundred and subtracting mentally. - Repeat with other pairs of 3-digit numbers.
Example: 400 400 - 300 = 1 00
300
4 1
2
99
4
ver. 2