One way they are different is that decimals are "parts of a whole" not necessarily a whole.
rounding whole numbers and decimals
No because whole numbers are integers without decimals or fractions
Factors must be whole numbers, not decimals.
Whole numbers contain no fractional part as do decimals
No because whole numbers are integers that do not have decimals or fractions attached to them.
Same rules as adding whole numbers with different signs.
Decimals are real numbers. Furthermore, integers and whole numbers are the same thing.
Decimals separate whole numbers from fractions.
in dividing decimals you never get a remainder and in dividing whole numbers you do. +++ More to the point perhaps, you are working in powers of 10 all the time.
Whole numbers are positive numbers and there are no fractions or decimals.