find the sum of all 4 digit numbers formed using digits 1,2 , 5,6 .
"( n - 1 ) ! * ( 111 . . . n ) * ( sum of the digits ) = ( 4 - 1 ) ! * 1111 * ( 1 + 2 + 5 + 6 ) = 93324 answer : a"
multiply(add(add(const_100, const_4), subtract(multiply(const_100, const_10), 1,2)), divide(add(divide(subtract(subtract(multiply(const_100, const_10), 1,2), add(const_100, const_4)), 1,2), const_1), const_2))