Digits are not Repeated

The total number of 5 digit numbers formed using the digits 2, 4, 6, 7, 8 if the digits are no repeated is

Digits are Repeated

Find the number of 4-digit numbers that can be formed using the digits 1, 2, 4, 5, 6, 8 if (a) digits can be repeated (b) digits cannot be repeated

The number of natural numbers less than 1000, in which no two digits are repeated is

How many numbers between 10 and 10,000 can be formed by using the digits 1, 2, 3, 4, 5 if Digits can be repeated

The number of 3 digits can be formed with the digits 1,2,3,4,5 when digits may be repeated is

The largest number form by digits 4,7,9 and 0 (taking all the digits and some digits may be repeated) is

The number of five digit telephone numbers none of their digits being repeated is