1. 1.7 Rounding Whole Numbers
Objectives
1. Locate the place to which a number is to be rounded.
2. Round numbers.
3. Round numbers to estimate an answer.
4. Use front end rounding to estimate an answer.
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Parallel
Example 2
Using Rounding Rules for 4 or Less
Round 643 to the nearest hundred.
Round 27,621 to the nearest thousand.
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Parallel
Example 3
Using Rounding Rules
a. Round 2271 to the nearest ten.
b. Round 14,972 to the nearest hundred.
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Parallel
Example 5
Rounding Large Numbers
Round 48,751 to the nearest ten-thousand.
Round 736 to the (a) nearest ten and (b) the nearest hundred.
nearest ten
b. nearest hundred
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Parallel
Example 6
Using Rounding to Estimate an Answer
Estimate each answer by rounding to the nearest ten. a. 28 41 91 + 46
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Parallel
Example 7
Using Rounding to Estimate an Answer
Estimate each answer by rounding to the nearest ten. b. 65 38 –
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Parallel
Example 8
Using Rounding to Estimate an Answer
Estimate each answer by rounding to the nearest ten. c. 72 46 x
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Parallel
Example 9
Using Rounding to Estimate an Answer
Estimate each answer by rounding to the nearest hundred. a.
723
285
197 +
644
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Parallel
Example 9
Using Rounding to Estimate an Answer
Estimate each answer by rounding to the nearest hundred. b.
832 –
274
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A convenient way to estimate an answer is to use front end
rounding. With front end rounding, we round to the highest
possible place so that all digits become 0 except for the first
one.
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Parallel
Example 10
Using Front End Rounding to Estimate an Answer
Estimate each answer using front end rounding. a. 38
1624
4178 +
339
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Parallel
Example 10
Using Front End Rounding to Estimate an Answer
Estimate each answer using front end rounding. b.
5162 –
875
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Parallel
Example 10
Using Front End Rounding to Estimate an Answer
Estimate each answer using front end rounding. c.
8250 x 36
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