Problem: the least number which must be subtracted from 6709 to make it exactly divisible by 9 is :
Rationale: "on dividing 6709 by 9 , we get remainder = 4 therefore , required number to be subtracted = 4 answer : c"
annotated_formula: subtract(6709, multiply(add(multiply(add(const_4, const_1), const_10), add(const_4, const_2)), 9))