A decimal number can be defined as a number whose whole number part and the fractional part is separated by a decimal point.

The dot in a decimal number is called a decimal point.

Explanation: For example, \$28.6\$.
Here, \$28\$ and \$6\$ are separated by a point. So, \$28.6\$ is a decimal number.

Decimals that have the same number of digits to the right of the decimal point are referred to as like decimals.

Explanation: For example, \$23.9\$ and \$25.8\$, in \$23.9\$ and \$25.8\$, there is only one decimal place after the decimal point, so \$23.9\$ and \$25.8\$ are like decimals.