When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
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* because 7 is greater than 5 most of the time when you add it to a two digit number you must carry which is another opportunity to make an error.
* it is not a multiple of 2 so you can't use counting by twos to help
* 9 is easy and there are may tricks to remember the multiples of 9s
* Therefore 7 is the most troublesome number.
@futurebird @jitterted Seems like just recently the most troublesome number is 4.
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@futurebird @jitterted Seems like just recently the most troublesome number is 4.
In some numerologies 4 is considered feminine while 5 is masculine. So, I always get a little salty when people hate on 4 because it seems vaguely sexist.
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird I have dyscalculia and anything larger than 6x6 I can't do in my head so 7x6 could be 56, I dunno
(aside to my middle school math teacher: I carry a calculator everywhere these days, now who's having the last laugh?!)
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird I simply do not multiply 7*8
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In some numerologies 4 is considered feminine while 5 is masculine. So, I always get a little salty when people hate on 4 because it seems vaguely sexist.
@futurebird @jitterted I was thinking specifically of this: https://www.theregister.com/security/2026/10/20/indian-certification-authority-emudhras-private-keys-compromised-one-of-them-was-the-number-4/5304312 It's become a bit of a meme lately.
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@futurebird Computer science is largely just a sillier version of math in general, so I've memorized single digit addition and multiplication, as well as powers of 2 which are important to computers.
I have to manually carry for anything beyond a single digit, which slows me down.I always imagined she was over-serious the silly child of mathematics is Pure Math
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@futurebird @jitterted And 7 has no easy pattern to learn. The easiest way to may be to flip it with the commutative property. You may not have 7 x 8 memorized, but you do know 8 x 7.
7 x 6 = 6 x 7
7 x 8 = 8 x 7
etc.@futurebird @jitterted 7 x 7 is a hopeless case. Hopefully, it never comes up.
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird For me it's connected to my "most remembered" part of multiplication table -> 7*7. Then I just add one more 7 to the result.
It's not that much slower than having it remembered, so I never bothered to "optimize" it. -
When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird 7749 (or 7642) and then continue the memorized sequence from there -
* because 7 is greater than 5 most of the time when you add it to a two digit number you must carry which is another opportunity to make an error.
* it is not a multiple of 2 so you can't use counting by twos to help
* 9 is easy and there are may tricks to remember the multiples of 9s
* Therefore 7 is the most troublesome number.
@futurebird @jitterted and have you looked at the decimal expansions when dividing?
1, great. 2, fantastic, ditto 4, 5, and 8. 3, 6, and 9 are all giving you infinite 3s or 1s or 6s or whatever, but at least it's all the same number. 7 is giving you its Dick van Dyke cockney accent impression of pi.
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird @whattherestimefor usually immediate — I did memorize “times tables” up to 12 in my youth, but I do occasionally forget one and have to work up or down from one that I do recall.
*My memory is pretty shit, so I’m surprised I remember as often as I do
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* because 7 is greater than 5 most of the time when you add it to a two digit number you must carry which is another opportunity to make an error.
* it is not a multiple of 2 so you can't use counting by twos to help
* 9 is easy and there are may tricks to remember the multiples of 9s
* Therefore 7 is the most troublesome number.
@futurebird @jitterted It's prime, not 2, and not a prime factor of our number base or base-1. In octal the nine-tricks work with 7.
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird
I used to get this confused with 6*9=54, so I think I really get it from 7*7=49+7=56. -
@futurebird
I used to get this confused with 6*9=54, so I think I really get it from 7*7=49+7=56.@futurebird
Also, the colors don't help. How do you get orange and white from green and purple? (Sometimes synaesthesia helps, but sometimes not!) -
When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
5*8 = 40 40+16=56
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird 7*8=56 immediately, however 8*7 needs to be converted to 7*8 to get to the answer
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird We had our times tables drilled into us, just as we were expected to write in cursive. Both were once considered essential life skills. Teachers told us that we wouldn't always have a calculator/computer to hand! Smartphones hadn't been conceived yet.
I'm told that many younger people have become increasingly reliant on technology, and that the education system now encourages this. If true, I'm not convinced this is progress.
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
@futurebird Today they ask ChatGPT? -
@futurebird I hated having to memorize times tables in elementary school. But I got fast at using the parts I did remember. So I would do 7*6 as (6*6)+6. And 8*6 as (6*6)+(2*6). So effectively I just memorized the 2, 5, 10 and square tables and derived everything else by addition and subtraction.
@KalenXI @futurebird same!
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When you need to multiply 7*8 do you simply have it memorized, or do you need to add, subtract or otherwise connect it to another math fact that you know better?
That is do you simply think "56" or are there more thoughts that lead to 56?
My autistic brain doesn’t do numbers. At all. So I’ll always ask my calculator app.
(and no, it’s NOT lack of practice. I did times tables as a child until I was blue in the face. I managed to memorise some of them like you would a chorus, or a poem. Still no idea how to do mental arithmetics. Which didn‘t prevent me from enjoying maths, especially algebra. Brains are funny creatures
)
