Rounding Decimals and Numbers
Decimal is a real number expressed in base 10. It is composed of digits and one decimal point. Each digit in relation to the decimal point has a particular value.
Since decimal is a base 10 number, each place has a value that is either ten times larger than the one on its right, or ten times smaller than the one on its left.
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Rounding makes numbers that are easier to work with in your head.
Rounded numbers are only approximate.
An exact answer generally cannot be obtained using rounded numbers.
Use rounding to get an answer that is close but that does not have to be exact.
How to round numbers
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Make the numbers that end in 1 through 4 into the next lower number that ends in 0. For example 74 rounded to the nearest ten would be 70.
Numbers that end in a digit of 5 or more should be rounded up to the next even ten. The number 88 rounded to the nearest ten would be 90.

Consider the number 4,827.
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4,827 rounded to the nearest ten is 4,830
4,827 rounded to the nearest hundred is 4,800
4,827 rounded to the nearest thousand is 5,000
All the numbers to the right of the place you are rounding to become zeros.
Here are some more examples:
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34 rounded to the nearest ten is 30
6,809 rounded to the nearest hundred is 6,800
1,951 rounded to the nearest thousand is 2,000
Rounding decimals works exactly the same way as rounding whole numbers. The only difference is that instead of rounding to tens, hundreds, thousands, and so on, you round to tenths, hundredths, thousandths, and so on.
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7.8199 rounded to the nearest tenth is 7.8
1.0621 rounded to the nearest hundredth is 1.06
3.8792 rounded to the nearest thousandth is 3.879
Here's a tip: to avoid getting confused in rounding long decimals, look only at the number in the place you are rounding to and the number that follows it.
For example, to round 5.3824791401 to the nearest hundredth, just look at the number in the hundredths place—8—and the number that follows it—2. Then you can easily round it to
5.38.

Do the following problems:
1) Round .09 to the nearest tenth
2) Round .005 to the nearest hundredth
3) Round .147 to the nearest tenth
.1
.01
.1
4) Round 3.045 to the nearest tenth 3.0
5) Round .00035 to the nearest thousandth 0
6) Round 1.87 to the nearest tenth 1.9
.01 7) Round .008 to the nearest hundredths
8) Round .04 to the nearest tenth 0
.05 9) Round .045 to the nearest hundredths
10) Round 15.56 to the nearest ones
11) Round 35.45 to the nearest tens
16
40
12) Round 482.001 to the nearest hundreds
13) Round 1,115.45 to the nearest tens
500
1,120
14) Round 32,845.92 to the nearest ten thousands 33,000
100,000 15) Round 100,035.03 to the nearest hundred
16) Round 292,929.29 to the nearest ten 292,930
17) Round 900,909.009 to the nearest thousand 901,000
18) Round 459,499 to the nearest ten thousands 460,000
19) Round 12,304,985 to the nearest hundred thousand 12,000,000
20) Janet took a measurement of the dress to be 25.67 inches wide. Rounded off to the nearest ones, how many inches wide would the dress be? 26
21) Beverly measured the wood at 233.569 inches. Rounded to the nearest tens, what would be the measurement? 200
22) Mark won the state lottery for $325,382,810. The lottery commission said that he would receive that amount rounded to the ten millions. How much would Mark be getting? $330,000,000