how many positive 3 - digit integers are divisible by both 3 and 7 ?
a number to be divisible by both 3 and 7 should be divisible by the least common multiple of 3 and 7 so by 21 . multiples of 21 between 100 and 999 , inclusive is ( last - first ) / multiple + 1 = ( 987 - 105 ) / 21 + 1 = 42 + 1 = 43 answer : a .
subtract(floor(divide(const_1000, lcm(3, 7))), floor(divide(const_100, lcm(3, 7))))