How to write repeating decimals with a bar

Some decimals end, and others go on forever. If a group of digits keeps repeating, we can write the group once and put a bar over it. The bar tells us exactly where the repeat starts.

Separate the part that repeats from the part that comes first

The decimal 32.18476 terminates because it has a last digit. In 32.184766666…, the digits 1847 come first and then the digit 6 repeats forever. Put the bar over just the 6.

32.184766666…=32.18476¯

A decimal can also go on forever without an eventually repeating pattern. For example, π starts 3.14159265… and has no repeating group to mark with a bar.

Put the bar over a group of two digits

In 0.54545454…, we see 54 followed by 54 again. The pattern starts right after the decimal point, so the bar goes over both digits.

0.54545454…=0.54¯

A zero can be part of the group too. In 0.07070707…, the repeating group is 07, so keep both digits under the bar.

0.07070707…=0.07¯