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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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 thanks to the early 80s obsession with times able memorisation, that's locked in as an instant response.
But I also have a couple of maths degrees, so can 'play' with the numbers in my head, using other facts and 'checking' my own memory.
Like 7*7 is 49, + 7 and yup, 56.
Or as others have commented, (7*2)*4 or (7*4)*2 also help.
Or 60 = 15 * 4, and 15 is 14+1 = 7*2+1, so 60-4 works too.
I basically never assume my memory is correct, I always error correct/sense check!
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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 know it instantly but only because the 7 and 8 tables were the ones I was struggling with the most. So I learnt the intersection. I still don't know the rest though
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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 know 8*8 is 64 off the top of my head and then I divide 8/2 to remove the 8th 8 from 64 to get 4. I then subtract 4 to get to 60 and subtract 4 again to get to 56. Don't ask me why. 8/2 is four. It works so don't judge. LOL Don't get me started how I do big numbers.🤭
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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 memorize just a few, to save my brain storage, so when I need to calculate, I get the closest memorized value and add the remaining. In this example, I get the memoried 7x7=49 and add 7 to get 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?
Mostly instant memory. But sometimes also `8*(8-1)` = `64 - 8`
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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 to rely on 8=2^3 and count 14, 28, 56.
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@passenger @danielaKay @kbm0 @futurebird
Most multiplication tables go up to 12 × 12 regardless of regional measurement systems. There is nothing inherently special about 12 in the imperial system (or whatever non-metric is called). Most clocks go up to 12 and people often refer to dozens.@sloanlance @passenger @danielaKay @kbm0 @futurebird there's definitely something special about 12 though - when you multiply a length, the inches part is capped at 12.
I guess it's not "special" in that there are multiple other numbers with the equivalent property - you could justify memorizing times tables up to 16s if you expect to do more arithmetic in pounds and ounces than in feet and inches for example.
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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 It's instant, but followed instantly by me checking my math to make sure it's accurate.
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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 : Well, in spite of my math minor, and a lifetime of computer worship, I have to admit that I was never able to *completely* memorize my multiplication tables. But I can usually remember most of them.
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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 parents promised me a reward if I learned the multiplication tables
(I didn't got to primary school much, in hospital too often).
I was thinking "maybe a bicycle".
I got a bottle of Lucozade.But I still remember the tables, instantly, and the Lucozade.
(English fizzy drink, supposedly healthy). -
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?
I wouldn’t be the first person to have memorized entire tables of multiplication.
Computing it is easy enough, but hash look up still works
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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 Oddly, perhaps, this is the last of the "multiplication table" I memorized (though that rote memory has eroded in later years). So, for me, it was "7x4x2" for most of my educational life.
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@futurebird 6*7 is 42, which I have memorized like most of the multiplications up to 12*12.
But 9*6 = 54 is one I can never remember on its own. I always go 8*6 and then add 6.
@aesthr @futurebird 6 * 9 = 42, though (in base 13)
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@tknarr @futurebird We are a memoized multiplication function with a years-long cache preflighting performed in advance.
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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 @StillIRise1963 I get 56 instantly and I voted that way but it’s worth noting that I did memorize the multiplication tables up through 12 at a very young age.
However beyond 12, I use different concepts of multiplication and addition and estimation to get the numbers.
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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 personally for good and fast muscle-memory outcome=derivation based on imprinted squares.
7*7=49 +7=50+(7-1) ==56 -
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've multiplied the single-digit numbers so many times in my head that I get 56 instantly, but when I was a kid I had an easier time remembering that 7*7 = 49 or 7*9 = 63 and then either adding or subtracting.
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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*2=14,14*2=28,28*2=40+(8*2=16)=56 is how I get there.
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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.
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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 usually instantly. When I'm having a bad day 8²-8 since squares are burnt into my brain for some reason (and within reason, magnitude-wise)
