I was teaching the classic Multiplying by 9’s trick and decided to punch it up a notch.
My students were in need of a more concrete way to use this trick {many of them kept mixing up the hands, counting fingers in the wrong direction…etc}.
My students were in need of a more concrete way to use this trick {many of them kept mixing up the hands, counting fingers in the wrong direction…etc}.
So we buddied up and wrote on our hands! They were freaking out!
If you are not familiar with the nines trick this is how it works:
I found these great posters:
- Number your fingers from left hand pinky to right hand pinky 1-10.
- Then take your problem like 9×8.
- Starting on the left {pinky labeled 1}, count until you get to the 8th finger {should be right hand middle finger}.
- Put that finger under. This is the division between the tens and the ones now.
- Count how many are on the left in the tens, and how many are on the right of the down finger and these are the ones.
- In the picture below, there are 7 fingers in all to the left and 2 to the right, therefore the number is 72
I had some not understanding the role that the “down” finger played so I made this into a “fence”. The fingers/numbers could no cross the fence. Then I had them make a T chart on their board to show the tens side and the ones side. Whatever finger they put down had to line up to the T chart and see what finger were in the “Ones Zone” and which were in the “Tens Zone”