Apparently, nines are the hardest to grasp for primary school children. If only they’d learned how to cheat like me, says Adrian Chiles
Apparently, nines are the hardest to grasp for primary school children. If only they’d learned how to cheat like me, says Adrian Chiles
The trick I was taught is that the sum of all two digit multiples of nine add up to nine. Then you just take the number you want to multiply times none and subtract 1.
For example if you want to multiply times 8, the tens place is 7 and the ones place must add up to 9, so 2. 7+2=9, so 9x8=72.
This is how I learned it too. It’s so fast in my head, I don’t even have to think about it.
Isn’t it easier to just do 80 - 8
not for me. I do the “adds up to 9” trick to this day.
The method I’m talking about only adds/subtracts single digit numbers, which is easier for kids.