How many $3$-digit numbers can be formed with the digits $1,2,3,4,5$ such that each digit can be used any number of times

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How many number of four digits can be formed with the digits 1,2,3,4,5 if the digit can be repeated in any number of times?

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How many three digit numbers can be formed by using the digits 0, 1, 3, 5, 7 while each digit may be repeated any number of times ?

Q. How many numbers of $3$ digits can be formed with the digits $1,2,3,4,5$ when digits may be repeated?

Q. How many $3$ digit numbers can be formed with the digits $1,2,3,4,5$ where digits may not be repeated?

Q. How many numbers between 30000 and 40000 can be formed with the digits 2,3,5,6,9 if each digit can be repeated any number of times?