how many times digit 2 is used while writing numbers from 400 to 700 ?
"in 400 to 500 there are 50 two ' s in 500 to 600 there are 50 two ' s in 600 to 700 there are 50 two ' s so total is 150 two ' s correct option : a"
add(add(divide(subtract(700, 400), const_10), multiply(add(const_10, const_1), add(const_10, const_1))), multiply(2, const_2))