calculate the sum of first 89 natural numbers .
"solution we know that ( 1 + 2 + 3 + . . . . . + 89 ) = n ( n + 1 ) / 2 therefore ( 1 + 2 + 3 + . . . . + 89 ) = ( 89 × 90 / 2 ) = 4005 . answer e"
multiply(add(89, const_1), divide(89, const_2))