Rounding to Decimal Places

A method of approximating a number using a nearby number at a given degree of accuracy is called rounding a number.

Rounding decimal places – Rules:

1. Retain the correct number of decimal places (e.g 1 for tenths, 2 for hundredth).

2. If the next decimal place value is greater than 4, increase the value in the last retained decimal place by 1.  

 

Rounding to Decimal Places - Examples

 

Example 1: Round 0.2386 to 3 decimal places.

Solution:

The 4th decimal number, 6, is bigger than 4, so we add 1 to the 3rd decimal number 8, and drop the rest of the decimal numbers.

Therefore answer is 0.239.


Example 2: Rounding a number 0.2385 to 2 decimal places.

Solution:

The 3rd decimal number, 8, is greater than 4, so we add 1 2nd decimal number 3, and drop the rest of the decimal numbers.

Therefore answer is 0.24.


Example 3: Round 4.6596356 to 4 decimal places.

Solution:

The fifth decimal number, 3, is less than 4, so we do nothing to the 6, and drop the rest of the decimal numbers.

Therefore answer is 4.6596


Example 4: Round 38.28577 rounded to the nearest whole number.

Solution:

The first decimal number, 2, is less than 4, so we do nothing to the 2, and drop the rest of the decimal numbers.

Therefore answer is 38.


Example 5: 23.45781 rounded to the nearest tenth.

Solution:

The first decimal number, 4, is equal to 4, so we do nothing to the 4, and drop the rest of the decimal numbers.

Therefore answer is 23.4.

 

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Example 6: 61.13248 rounded to the nearest hundredth.

Solution:

The 3rd decimal number, 2, is less than 4, so we do nothing to the 3, and drop the rest of the decimal numbers.

Therefore answer is 61.13

 

Rounding to Decimal Places - Practice

 

Problem 1: 83.74648 rounded to the nearest hundredth.

Answer: 83.75

Problem 2: 57.94642 rounded to the nearest thousandth.

Answer: 57.946

Problem 3: 8.74878 rounded to the nearest thousandth.

Answer: 8.749