What the !!!!!!!!!!!!!!!!!!!!!! ????

Have you ever wondered what the ! symbol is doing on your calculator? 


You can use it to help solve these sorts of questions...





If you have a horizontal row of four blocks, how many different ways can you arrange the order of them in the row? 

Method 1:

Set up a grid and put the letters in. Something like RISK, RSIK, RKSI, etc. 

This is fairly time consuming and RISK(y). You will be prone to mistakes by forgetting some combinations. It is not practical for questions with larger numbers of blocks.

Method 2: Find the ! on your scientific calculator. It may be indicated as x! You may have to hit a shift or 2nd function as well, in order to activate this handy tool. So...

Enter 4 (your number of blocks) and activate the !    Answer is 24

Method 3: If you don't have a calculator... 4x3x2x1 = 24. 4 is the number of blocks and you multiply it by the 3 whole numbers that are smaller than 4 and greater than 0. If you had 5 blocks, you would work out 5x4x3x2x1 = 120