Hello there, my fellow human being!
So, let's use the important information that was put in this word problem:
400 store santas were hired.
Each santa sees 125 children a day.
This continues for 30 days.
We can now figure this out.
400 * 125 = 50,000 children a day seen by all the santas
50,000 * 30 = 1,500,000 children seen by all the santas in 30 days total.
So, 1,500,000 children are seen by Lord and Taylor's santas.
Hope this helped!
~Ruru