Decimals are a method of writing fractional numbers without writing a fraction having a numerator and denominator.

The fraction 7/10 could be written as the decimal 0.7
The period or decimal point indicates that this is a decimal.

The decimal 0.7 could be pronounced as SEVEN TENTHS or as ZERO POINT SEVEN.

There are other decimals such as hundredths or thousandths. They all are based on the number ten just like our number system.

A decimal may be greater than one. The decimal 3.7 would be pronounced as THREE AND SEVEN TENTHS.