Rounding Decimals

Rounding Decimals

In this post, you learn how to round decimals in few simple steps.

Step by step guide to rounding decimals

  • We can round decimals to a certain accuracy or number of decimal places. This is used to make the calculation easier to do and results easier to understand when exact values are not too important.
  • First, you’ll need to remember your place values: For example:
    \(12,4568\)
    \(1\):tens, \(2\): ones, \(4\): tenths,
    \(5\): hundredths, \(6\): thousandths, \(8\): tens thousandths
  • To round a decimal, find the place value you’ll round to.
  • Find the digit to the right of the place value you’re rounding to. If it is 5 or bigger, add 1 to the place value you’re rounding to and remove all digits on its right side. If the digit to the right of the place value is less than 5, keep the place value and remove all digits on the right.

Example 1:

Round \(1.9287\) to the thousandth place value.

Solution:

First look at the next place value to the right, (tens thousandths). It’s \(7\) and it is greater than \(5\). Thus add \(1\) to the digit in the thousandth place.
The thousandth place is \(8\). \(→ 8 \ + \ 1=9\), then, the answer is (1.929)

Example 2:

Round \(9.4126\) to the nearest hundredth.

Solution:

First, look at the next place value to the right of hundredth place. It’s \(2\) and it is less than \(5\), thus remove all the digits to the right. Then, the answer is \(9.41\).

Example 3:

Round \(2.1837\) to the tenth place value.

Solution:

First look at the next place value to the right, (hundredth). It’s \(8\) and it is greater than \(5\). Thus add \(1\) to the digit in the tenth place.
Tenth place is \(1\).
\( → 1+1=2\), then, the answer is \(2.2\)

Example 4:

\(2.1837\) rounded to the nearest hundredth.

Solution :

First, look at the next place value to the right of hundredth. It’s \(3\) and it is less than \(5\), thus remove all the digits to the right. Then, the answer is \(2.18\).

Exercises

Round each decimal number to the nearest place indicated.

  • \(\color{blue}{0.\underline{2}3} \)
  • \(\color{blue}{4.\underline{0}4} \)
  • \(\color{blue}{5.\underline{6}23} \)
  • \(\color{blue}{0.\underline{2}66} \)
  • \(\color{blue}{116.\underline{5}14} \)
  • \(\color{blue}{8.\underline{0}6} \)

Download Rounding Decimals Worksheet

Answers

  • \(\color{blue}{0.2} \)
  • \(\color{blue}{4 }\)
  • \(\color{blue}{5.6} \)
  • \(\color{blue}{0.3} \)
  • \(\color{blue}{116.5}\)
  • \(\color{blue}{8.1} \)

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