من طرف If we have the digits 1, 2,3, 4, 5,6,7 , find
(i) How many 4 - digits number can be formed without repeating.
(ii) How many 7 - digits number can be formed without repeating
(iii) How many 5 - digits number started with the digit 4, can be formed
(i) How many 4 - digits number can be formed without repeating.
(ii) How many 7 - digits number can be formed without repeating
(iii) How many 5 - digits number started with the digit 4, can be formed
