Multiples of Nine.

Here is a website that is worth checking out.

> http://www.regiftable.com/RegiftingRobinPopUp.html

You are asked to pick a 2 digit number and then subtract those 2 digits from your number. ex. you choose 48 and subtract 4 and 8 from it. Your number is 36

You then find your number on a page of numbers and a matching gift.

The computer then tells you the exact gift you chose.

How?

Have the class solve the problem. Have each student choose a number and subtract the two digits. List the numbers.

36, 45, 81, 18, 27

Do you see a pattern?

3+6, 4+5, 8+1

Now take a second look at the gift page. What is listed for 9, 18, 27, 36....?

Ed Tech Digest

6 hours ago