Find cells based on content and trim to left 3 characters

I need to include some code in my project that will select any cell containing "tier" and then trim to the first three characters.

The cell will always be in column A but could be any row.
There will be cells in two different sheets in the workbook.

Typical:   "300.00 - Tier 3" or "500.0 - Tier 2"  should result in "300" & "500"

Thanks!!
MWT-sample.xlsx