how many two - digit numbers that do not contain the digits 1 or 4 are there ?
"we can have 7 digits ( 2 , 3,5 , 6,7 , 8,9 ) for the first place ( tenth ' s place ) . and similarly 8 digits for the unit digit . ( 0,2 , 3,5 , 6,7 , 8,9 ) so in total 7 * 8 = 56 hence b"
multiply(multiply(multiply(const_10, const_10), subtract(const_10, const_1)), 4)