Yes, a whole number can be a decimal.
A decimal is a number that is expressed in base-10 notation and has a fractional component, indicated by a decimal point. For example, the number 3.14 is a decimal because it has a fractional component (0.14) indicated by the decimal point.
On the other hand, a whole number is an integer that is greater than or equal to 0. For example, 0, 1, 2, 3, 4, etc. are all whole numbers.
So, a whole number can be expressed as a decimal by adding a decimal point and a fractional component of 0 after it. For example, the whole number 5 can be expressed as a decimal as 5.0.