The Nifty Nine Times Table

Today we explored how amazing the 9x tables are.
We discovered how to use our fingers to do our 9x tables:

Put your hands in front of you and spread out your fingers.
For 9 x 3 bend your third finger down. (9 x 4 would be the fourth finger etc...)
The fingers to the left of the folded finger are the tens ie: 2 fingers are 2 tens = 20
The fingers to the right of the folded finger are the ones ie: 7 fingers are 7 ones = 7
So the answer is 27.

The 9 x Table
1 × 9 =  9

2 x 9 = 18

3 x 9 = 27

4 x 9 = 36

5 x 9 = 45

6 x 9 = 54

7 x 9 = 63

8 x 9 = 72

9 x 9 = 81

10x 9 =90

 

Look at the answers on the right-hand side of the table above. Notice how the tens go up

but the ones go down.

All the digits in the 9 × table add up to 9.

18 = 1 + 8 = 9

27 = 2 + 7 = 9

36 = 3 + 6 = 9

Look at the pattern to the right: the ones column goes down one at a time and the tens column goes up.  You can see how the 9 x table reverses itself!

(1 × 9) 09 ~ 90 (10 × 9)

(2 × 9) 18 ~ 81 (9 × 9)

(3 × 9) 27 ~ 72 (8 × 9)

(4 × 9) 36 ~ 63 (7 × 9)

(5 × 9) 45 ~ 54 (6 × 9)

(6 × 9) 54 ~ 45 (5 × 9)

(7 × 9) 63 ~ 36 (4 × 9)

(8 × 9) 72 ~ 27 (3 × 9)

(9 × 9) 81 ~ 18 (2 × 9)

(10 × 9) 90 ~ 09 (1 × 9)

You can see the pattern the

9 x table makes on the 100's board 

We were amazed at how easy the 9 x are to learn once we discovered the patterns the numbers make.