how many 6 digit number contain number 4 ?
"total 6 digit no . = 9 * 10 * 10 * 10 * 10 * 10 = 900000 not containing 4 = 8 * 9 * 9 * 9 * 9 * 9 = 472392 total 6 digit number contain 4 = 900000 - 472392 = 427608 answer : d"
add(subtract(subtract(const_1000, const_10), multiply(multiply(const_10, multiply(6, 6)), multiply(const_4, const_2))), const_10)