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# Rounding

To reduce the number of decimal places in a number, you can round it.

$\Tblue{2.3}45$ rounded to one decimal place is $\Tblue{2.3}$

$\Tblue{2.34}5$ rounded to two decimal places is $\Tblue{2.3}\Torange{5}$.

To round a number:

• Decide how many decimal places you want to keep.
• Look at the digit after the last digit you want to keep.
• If this digit is $\le 4$, you round down and remove everything after the digit you want to keep.
• If this digit is $\ge 5$, you round up by adding one to the last digit you are keeping, and then remove everything after this.

Here are a few numbers rounded to two decimal places. The red digit is the first to be removed, it determines if we round up or down. Modified digits are in orange.

 $\Tblue{2.34}\Tred{4}6$ $\Tblue{3.45}\Tred{6}78$ $\Tblue{45.89}\Tred{9}$ $\Tblue{-129.09}\Tred{1}23$ $\Tblue{12.1}$ $\Tblue{2.34}$ $\Tblue{3.4}\Torange{6}$ $\Tblue{45.}\Torange{90}$ $\Tblue{-129.09}$ $\Tblue{12.1}$