You will need a simple calculator for this activity.

Put a 3-digit number into your calculator. Next, without clearing the calculator, enter the number again. For example, if your number is 487, you should have 487487 in the display. Divide this number by 13. Then, divide the result by 11. Finally, divide by 7. What do you get? Try it two or three more times to see if you are noticing what is going on.

Explain why this always happens. What is the mathematics?

abcabc = abc*1000 + abc*1 = abc(1001)

13*11*7=1001

and

abcabc/1001 = abc

In our example:

487*1000                 =  487000

                  +  487*1 =        487

487*1000 +  487*1  =  487487