1. Click your or arrow keys to move the card ahead! For your IPAD swipe the screen. Using Your Abacards® Click/Swip and follow along using your abacus. After each click say what you saw. Practice saying what you will see before you click! After using the Abacards ®, make up problems. Forward Backward 10 x 10 Square Border Problem

2. If you make a square with 100 tiles, how many tiles must you paint grey to make a complete border. Try not to count! 10 x 10 Square Border Problem 10 Tiles

3. 10 + 10 + 8 + 8 How Many Tiles Make Up The Edge of a 10 x 10 Square?

4. 9 + 9 + 9 + 9 How Many Tiles Make Up The Edge of a 10 x 10 Square?

5. 10 + 9 + 9 + 8 How Many Tiles Make Up The Edge of a 10 x 10 Square?

6. 8 + 8 + 8 + 8 + 4 How Many Tiles Make Up The Edge of a 10 x 10 Square?

7. 8 + 8 + 8 + 8 + 4 = 9 + 9 + 9 + 9 = 10 + 10 + 8 + 8 =20 + 16 = 18 + 18 = 16 + 20 = 10 + 9 + 9 + 8 =18 + 18 =

8. How Many Tiles Make Up The Edge of a n x n Square? (n-2)+(n-2)+(n-2)+(n-2)+4 = 9 + 9 + 9 + 9 = 10 + 10 + 8 + 8 = 4n - 4 n + n + (n-2) + (n-2) =4n - 4 (n-1)+(n-1)+(n-1)+(n-1) = 4n - 4 8 + 8 + 8 + 8 + 4 = 10 + 9 + 9 + 8 = n + (n-1) + (n-1) + (n-2) = 4n - 4

9. There are at least 2 questions left! Does 4n – 4 work for all squares of side n? Can we find another solution using area?

10. 10 x 10 How Many Tiles Make Up The Edge of a 10x10 Square? - 8 x 8