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Estimating Sums and Differences. Rounding Clustering Front-end-estimating. 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. Example: Estimate the sum of 10.93 and 3.25. 11. 11.00.
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Estimating Sums and Differences Rounding Clustering Front-end-estimating
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.
Example: Estimate the sum of 10.93 and 3.25. 11 11.00 10.93 3.00 3 3.25 + 14
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
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.
Example 5.45 9.89 3.53 6.03 Front-end: 5 + 9 + 3 + 6 = 23 + About 23