Find the number of 6 digit numbers that ends with 21 (eg. 537621), without repetition of digits

Find the number of 6digit numbers that ends with 21( eg.537621), without repetition of digits

What is the number of five-digit numbers formed with 0, 1, 2, 3, 4 without any repetition of digits ?

Find the number of 3-digit numbers, formed with the digit (2,5,4,6) when repetition of the digits is allowed.

Find the number of 6-digit numbers using the digits 3,4,5,6,7,8 without repetition. How many of these numbers are (a) divisible by 5 (b) not divisible by 5

The sum of all five digit numbers formed with the digits 1,2,3,4,5 without repetition of digits are