Rounding decimals to the nearest whole number or the tenths, hundredths, thousandths is easy!

In this post we are going to learn to round decimal numbers. Rounding decimals helps us to manage the numbers more easily in order to operate them.

Rounding decimals to the nearest whole number

To round a number to the nearest whole number, you have to look at the first digit after the decimal point.

If this digit is less than 5 (1, 2, 3, 4) we don’t have to do anything, but if the digit is 5 or greater (5, 6, 7, 8, 9) we must round up.

Rounding Decimals

Examples:
  • Round the following number to the nearest whole: 5.36

We notice the digit after the decimal point is 3. Since it is less than 5, the number is closer to 5 than to 6, and so the rounded whole number is 5.

  • Round the following number to the nearest whole unit: 32.74

We notice the digit after the decimal point is 7. Since it is greater than 5, the number is closer to 33 than to 32.  The rounded whole number is 33.

Rounding decimals to the tenths, hundredths, thousandths…

To round a decimal number we have to look at the number after the one we want to round to. If we have to round to the nearest tenth, we focus on the digit in the hundredths place. If we have to round to the nearest hundredth, we focus on the digit in the thousandths place. If this digit is less than 5 (1, 2, 3, 4) we don’t have to do anything, but if it is 5 or greater (5, 6, 7, 8, 9), we must round up.

Examples:
  • Round the following number to the nearest tenth: 10.386

We focus on the digit after the tenths place (in the hundredths place), which is 8. Since 8 is greater than 5 we have to round up in the tenths place. The rounded number is 10.4, which means that 10.388 is closer to 10.4 than to 10.3

  • Round the following number to the nearest hundredth: 0.4838

We focus on the digit after the hundredths place (in the thousandths place), which is 3.  Since it is less than 5, we don’t change the digit in the hundredths place. The rounded number is 0.48. Wich means that 0.4838 is closer to 0.48 than to 0.49

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