## Tuesday, June 12, 2012

### Speed! - Patterns in the Cards - Doubles

This is the third post in an extension of the Speed! Patterns in the Cards posts. - I created the fun card game Speed! to teach multiplication. It uses skip counting to teach children to multiply and how to multiply faster. The series of Patterns in the Cards blog posts are meant to show some activities that can aid in number sense development using the Speed! cards.

Cool patterns become visible when two decks of Speed! cards are placed one on top of the other matching numbers. Last week we found that if the base deck was a multiple of the top deck all the cards in the base deck would be covered.

If you tried the additional activities from last week the base deck cards would again be covered.

Base Deck       Top Deck
Eight Speed        Four Speed
Six Speed           Three Speed
Nine Speed         Three Speed

What do you think will happen if the top deck is two times the base deck? For example, if Four Speed is the top deck and Two Speed is the base deck. (Four is 2 times Two).

First lay Two Speed, the base deck out like this.

- Now get out Four Speed and find the cards the two decks have in common (4, 8, 12, 16 and 20). If Two Speed was extended it would also conatin the common cards 24, 28, 32, 36 and 40.
- Lay the common cards from Four Speed on top of the corresponding Two Speed cards.

If Two Speed is extended up to 80 and corresponding Four Speed cards are placed on top, your cards should look like this.
It's a checkerboard pattern!

Now try some more doubles and see what happens.
Base Deck       Top Deck
Four Speed        Eight Speed
Three Speed      Six Speed

There is another way to make a checkerboard pattern. See if you can find it before next week's post.