All those are rational numbers because they are all terminating decimals. Irrational numbers are non-terminating non-repeating decimals, like this 1.01001000100001000001000001··· where that keeps going forever. It never repeats the same block of digits because each block gets one more 0 than the previous block. Other examples of irrational numbers are, , , . When expressed as a decimal those will never repeat the same block of digits forever. Edwin