Problem: how many four - digit numbers that do not contain the digits 3 or 6 are there ?
Rationale: "1 st digit can be filled up by the numbers - { 1 , 2 , 4 , 5 , 7 , 8 , 9 } = 7 ways 2 nd digit can be filled up by the numbers - { 0 , 1 , 2 , 4 , 5 , 7 , 8 , 9 } = 8 ways 3 rd digit can be filled up by the numbers - { 0 , 1 , 2 , 4 , 5 , 7 , 8 , 9 } = 8 ways so , total no of ways is 7 * 8 * 8 = > 3584 hence answer will be ( b )"
annotated_formula: multiply(multiply(multiply(const_10, const_10), subtract(const_10, const_1)), 6)