5 digit number divisible by 4

It is the formula...5^n-1, where n is no of digits..

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Divisibility rule of 4 is last two digits are divisible by 4
so in 5 digit no last two digit should always be 12,24,32,44,52;
(any one of them may be)

so for last two digits 5 ways are possible ;

since repetion are allowed then for 3rs place form right there are also 5 ways so in 3rd place either of 1,2,3,4,5 is possible;
simillarly at 4 rth place either of 1,2,3,4,5 is possible so again 5 ways are possible

simillarly at 5th place also 5 ways are possible

so total no are: 5*5*5*5=625