1. Estimating Sums and Differences Rounding Clustering Front-end-estimating

2. Rounding Most of the time, you will be asked to round to the nearest whole number. Round to the ones place, and drop the decimal part of your number.

3. Example: Estimate the sum of 10.93 and 3.25. 10.93 + 3.25 11 11.00 3.003 14

4. Clustering Use when all numbers are close to the same amount If so, round each number to the same number. Then multiply Ex) $2.44 + $1.86 + $2.11 + $1.70 $2 x 4 = $8

5. Front End Estimation Add or subtract the values of the digits in the front place or left-most place value. Usually gives a sum that is less than the actual sum.

6. Example 5.45 9.89 3.53 6.03 + Front-end: 5 + 9 + 3 + 6 = 23 About 23