Rounding decimals

Rounding using rules

We can round numbers using conventions or rules for rounding. We refer to the digit to be considered as the rounding digit. For example, if the number 3.168 is to be rounded to 2 decimal places then 6 is the rounding digit.

When the rounding is completed, the digits following the rounding digit are discarded.

Following this convention 3.168 is 3.17 when rounded correct to 2 decimal places.

Illustrating rounding using a number line

Question 1

Round 6.72 correct to 1 decimal place (tenths).


  Diagram of a number line starting from 6.7 to 6.8 with an increment of 0.01. Red arrow pointing to 6.72.  
  As shown on the number line, 6.72 is closer to 6.70 than to 6.80.