given the digits 0,1,2,3,4,5,6, and 7 find the number of possibilities in each category four digit numbers, odd three digit numbers and three digit numbers without repeating digits.

Answer 1

In each case we can assume that no whole number starts with a zero, and no repeating digits for all 3 cases.

number of 4 digits numbers = 6x6x5x4 = 720
number of 3 digit odd numbers, (must end in an odd) = 5x5x3 = 75

number of 3 digit numbers = 6x6x5 = 180