How many different three-digit numbers can be formed using the digits 2, 4 and 6 if each digit can be used:
a). as many times as you would like
We do not give answers. We help you solve the problem on your own. After all, when you take the test, we shall not be there to give you the answer.
I am going to give you a hint. This problem looks hard but becomes considerably easier if you break it down into parts.
How many distinct three-digit numbers can be formed using one of the digits 2, 4, and 6 three times?
If you learned some counting formulas, which formula applies to the question above? (You do not need a counting formula for this easy a problem, but it is good to see that the formula gives the same answer as common sense.)
How many distinct three-digit numbers can be formed using 4 twice and 2 once?
So, how many distinct three-digit numbers can be formed using one of the digits 2, 4, and 6 twice and either of the other two digits once?
This idea of breaking a problem into several easier problems is useful in many parts of mathematics.