Write the least number possible with 5 in the thousands place

so it must look like

5xxx
to be as small as possible we need:
5000

To find the least number possible with 5 in the thousands place, we need to keep the other digits as small as possible.

Since the thousands place is the first digit from the left, the other digits are in the hundreds, tens, and ones place. To make them as small as possible, we can use zeros.

Therefore, the least number possible with 5 in the thousands place is 5000.