Rounding Decimal Numbers

Decimal numbers, such as O.6495, have four digits after the decimal point.  Each digit is a different place value.  

The first digit after the decimal point is called the tenths place value. There are six tenths in the number O.6495.

The second digit tells you how many hundredths there are in the number.  The number O.6495 has four hundredths. 

The third digit is the thousandths place. 

The fourth digit is the ten-thousandths place which is five in this example. 

Therefore, there are six tenths, four hundredths, nine thousandths, and five ten-thousandths in the number 0.6495.

Rounding decimals is very similar to rounding other numbers. If the hundredths and thousandths places of a decimal is forty-nine or less, they are dropped and the tenths place does not change.

For example, rounding 0.843 to the nearest tenth would give 0.8.

If the hundredths and thousandths places are fifty or more, the tenths place is increased by one. The decimal 0.866 rounded to the nearest tenth is 0.9

Rounding decimals is very similar to rounding other numbers. If the thousandths place of a decimal is four or less, it is dropped and the hundredths place does not change. For example, rounding 0.843 to the nearest hundredth would give 0.84.

If the thousandths place is five through nine, the hundredths place is increased by one. The decimal 0.846 rounded to the nearest hundredth is 0.85. 

27.17469 rounded to the nearest whole number is 27
36.74691 rounded to the nearest whole number is 37
12.34690 rounded to the nearest tenth is 12.3
89.46917 rounded to the nearest tenth is 89.5
50.02139 rounded to the nearest hundredth is 50.02
72.63539 rounded to the nearest hundredth is 72.64
46.83531 rounded to the nearest thousandth is 46.835
9.63967 rounded to the nearest thousandth is 9.640

Rules for rounding decimals.
1. Retain the correct number of decimal places (e.g. 3 for thousandths, 0 for whole numbers)
2. If the next decimal place value is 5 or more, increase the value in the last retained decimal place by 1.

Home Task

Rounding Worksheet 1

1a.   Round 4.47 to one decimal.	1b.   Round 5.751 to two decimals.
2a.   Round 5.38 to two decimals.	2b.   Round 556.79 to two decimals.
3a.   Round 4.489 to two decimals.	3b.   Round 0.827 to one decimal.
4a.   Round 28.89 to two decimals.	4b.   Round 7.95 to one decimal.
5a.   Round 54.67 to two decimals.	5b.   Round 20.699 to one decimal.
6a.   Round 811.58 to one decimal.	6b.   Round 8.52 to two decimals.

 

Rounding Worksheet 2
Round the following numbers to the accuracy of the underlined digit.
For example, 5678 means you round to the nearest ten.

1a.   0.74443	1b.   0.69695	1c.   95.5319
2a.   643.3135	2b.   4.72	2c.   8.4804
3a.   56.24417	3b.   50.48496	3c.   42.48015
4a.   8.26257	4b.   0.81568	4c.   5.0864
5a.   2.65463	5b.   6.5237	5c.   55.1439
6a.   567.7316	6b.   0.16266	6c.   75.1457

Rounding Worksheet 3

Rounding Worksheet 4