A number is natural if it is one of the counting numbers (greater than 0), i.e., 1,2,3,4,5,...
Whole Numbers are positive numbers, including 0, with no decimal or fractional parts
Integers are a whole number (no fractions or decimals) positive or negative including the number 0, ...,-5,-4,-3,-2,-1,0
Imaginary numbers are the square root of a negative number