A whole number consists of the 2 4, 6, 8, and 0. How many whole numbers are possible?
321 using a single copy of each number.
A whole number is a number that sits within the range
We can make whole numbers using one, some, or all of the numbers listed. I'm going to assume that we can only use a single copy of each number, so the number
Before we start, I'm noticing that if we make a 2-digit number starting with
1-digit = 1
For 2-digit numbers, we have a permutation of five numbers, select 2:
For 3-digit numbers, we do the same for five numbers, pick three:
For 4-digit numbers, we do the same for five numbers, pick four:
And now we do the 5-digit numbers:
And now we add them up: