Explanation:
Start with 11, and count down until you reach 1. Multiply everything along the way.
11*10*9*8*7*6*5*4*3*2*1 = 39,916,800
Or a shortcut would be to say
11! = 39,916,800
The exclamation mark means factorial. It tells the calculator to follow the instructions mentioned above.
The number 39,916,800 is a little over 39.9 million, or you could say it's a bit smaller than 40 million.
