how many unique positive odd integers less than 80 are equal to the product of a positive multiple of 5 and an odd number ?
"the question basically asks how many positive odd integers less than 80 are odd multiples of 5 so we have 5,15 , 25,35 , 45,55 , 65,75 = 8 b"
divide(divide(80, 5), const_2)