You, an intellectual: 9+7=16
Me, with ADHD: if you take 1 from 9 and give it to 7 thats 8+8 and 8x2 is 16
Someone, usually a Teacher: NOT LIKE THAT YOU HEATHEN
This is literally how I would have done it
9 is a hungry bitch and takes one from 7, making it 10+6=16
VALID
Hey this also applies to larger head math in case anyone wants that. What’s 24 x 6?
24/2 = 12. 6 x 2 = 12
12 x 12 = 144.
If you can get two terms into squares, it’s much easier. With things that aren’t able to be made into squares like 15 x 69?
69 x 15 = (69 x 10) + (69 x 5)
Anything times 10 is easy; just add a zero.
69 x 5 = (60 x 5) + (9 x 5)
Again, 60 x 5 is easy; it’s just 30 with another zero, and we all know 9 x 5 is 45.
So now you just have to add
69 x 10 = 690 +
60 x 5 = 300 +
9 x 5 = 45 = 1035.
I use this more in retail where people are always asking me the price of things. What’s 40% of $79.50?
7.9 is 10%
7.9 is ~8.
100% - 40% = 60%
6 x 10%(~8) = ~48.
“48-ish” leaves the customer pretty satisfied and it’s impressive once you’re practiced at it and don’t need a calculator to do it. It’s even more useful when you’re selling credit cards and someone wants to know how much they save on a large purchase.
Basically, the ADHD way of subdividing and reapproaching can be much more useful than just memorizing and is actually a huge fundamental of algebra.
