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10 + 7 = 17 17- 1 = 16
The legend said that it is how Gaussian elimination was discovered in europe
A dozen years ago or so there was a huge uproar about “common core” mathematics, which was a new standard being used in the USA for teaching.
It was a politicized trendy topic and even so-called-intellectuals were jumping on the train and calling it a deranged way of learning math.
I looked into it a bit, and I swear this pic pretty much sums up one of the key methods they were teaching.
Basically just tricks that a lot of people figure out to simplify problems.
That’s exactly what it is. A way to help conceptualize and play with numbers. Stuff my bored ass was doing in school anyway before common core came around lol
9 is one less than 10, and 7 is three less than 10, so combined, they’re four less than 20 = 16
Idk I have adhd and my working memory is so poor that memorizing time tables was the only way. :/
I thought you give 1 from 7 to 9 so it becomes 10+6 !!
I mean, sure, the choice of the “nice” numbers here is eccentric, but this is essentially the way math is taught nowadays. Only, instead of making 8 in this special case, the goal is usually to make 10 + leftovers because adding to 10 is always easy.
Here’s my (upper midwest) spicy mental math take: it should be big-endian and solved with backtracking for ripple carry/borrow. None of this starting-from-the-1’s-place-and-successively-incorporating-higher-order-digits nonsense. Extended carry/borrow is rare, and if you start with the most significant digits and give up/get bored part way through, the intermediate answer is in the ballpark of the real answer.
Why wouldn’t you take the 1 from the 7 so it is 10+6?
This is what I go for…Just play in 10s. Alot easier IMO
NOT LIKE THAT YOU HEATHEN
The answer is 69
420% of the time.Niiiiice
No take one from 7 and its 10+6=16
Take 7 from 7 and its 16+0 =16
Take 11 from 7 and it is 20-4=16
This is how I think for sure.
And here I always thought it was 1001 + 0111 = 10000.
not even ADHD related you’re just taking a route to something more readily available in your memory. that’s how brains are supposed to work.
to me the detour is -1+10. whenever i see a 9 i take 1 away from the other guy and then add 10.
9 x single digit mumber works similarly; except i take away 1 and complete that to 9 by adding a number next to it.
9x7 = ?
7-1 = 6
6+? = 9
9x7 = 63
9x7 = 70 - 7 = 63 in table of 9 too easy ! (nearly the same technic)
8x7 = 70 - 7x2 = 70 - 14 = 6 + 70 - 20 = 56 (6 from 10-4 from 14)7x6 = 5x7 + 7 = 70/2 +7 = 35 + 7 = 42 the answer to the life, the death and all the rest (5xa = 10/2 x a= 10a/2)
i mentioned the 5x trick elsewhere under this post but for me for some reason doing the halfing first is easier. so to me it’s a/2x10 instead.
This is literally how common core math works.
This is psychopathy. Clearly you just add the 1 to the 9 to make it 10 and subtract it from the 7 to get 6 and 10+6 = 16.
I’ve always done it this way and don’t have adhd
