If

represents the pounds of poultry the caterer had originally, then serving 45 pounds from that amount would be
subtracting it from the original amount, leaving them with

pounds of poultry. We're told that this new weight is more than, or
greater than, 10 pounds. The > sign captures that fact nicely. Our inequality then becomes:

Which means "p pounds of poultry, minus 45 pounds, is heavier than 10 pounds."
Edit: Solving that inequality by adding 45 to both sides, we find that

Which means that the caterer started with
more than 55 pounds of poultry.