how many multiples of 7 are there between 9 and 89 , 9 and 89 inclusive ?
"7 multiples are . . . 14 , 21,28 , 35,42 , 49,56 , 63,70 , 77,84 , . . . , . . . , the answer is = 11 answer is a"
add(divide(subtract(89, 9), 7), const_1)