Use the digits 4, 5, 6, and 8. Make as many factor pairs as you can that have a product between 3,000 and 5,000
Write down all the possible numbers with those digits
and test them. [
4(4444)=17786 which is too high so there can be no 4 digit factors.
888 is the highest 3 digit factor and 888(4)=3552 so it works but only with 4.
4(750)=3000, so 4 can be paired with every number between 750 and 888. You are only allowed the digits 4,5,6,and 8so discard the numbers which include other digits.
Use the same
process with 5, 6 and 8, always finding the highest and lowest number that works and using all the numbers in between in the pairs.
There are 64 three digit numbers with these digits, 16 2 digit numbers and 4 one digit numbers. Write them all down and systematically find which ones work.
Remember not to count pairs twice. For example 56,52 si the same as 52,56. You do not have to actually multiply out every
combination if you find the highest and lowest factors that can be paired with each individual factor.