How many integers less than 84 are relatively prime to 30?
Factors of 30 = 2,3,5,6,10,15,30
Relatively prime to 30
83, 79, 77, 73, 71, 67, 61, 59, 53, 49, 47, 43, 41, 37, 31, 29, 23, 19, 17, 13, 11, 7
1 , 7 , 11 , 13 , 17 , 19 , 23 , 29 , 31 , 37 , 41 , 43 , 47 , 53 , 55 , 59 , 61 , 65 , 67 , 71 , 73 , 79 , 83 >>Euler'sPhi = 23
