Question 1037705
You start with 15. Select a student and a chair. Now you have 14 to go. So you select another student and another chair. And you have 13 to go. And so on. How do you write this? This is how:
15! This means 15*14*13*12*11... etc, down to 1. Your calculator very likely has the ! key.
15! = 1,307,674,368,000 or in scientific notation: 1.307674368×10^12