30/5 is a natural number, whole number, integer, rational number?

rational because rational means fraction but if you simplify it is a whole number

All of them! 5 goes into 30 6 times, which means that 30/5 = 6. 6 is a whole number, a natural number (a positive whole number) an integer (all whole numbers are integers), and a rational number (since it can be written as a ratio between the whole numbers 30 and 5)