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?
Mostly I have that one memorized. Otherwise, I decompose it into 5*8 + 2*8, which is 40 + 16.
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Look at the edit history if you want a laugh.
If that's how your brain is working this morning, I recommend you don't play around with 57 just now:
https://hsm.stackexchange.com/questions/6358/story-of-grothendiecks-prime-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?
The bigger question is: are the hardest ones 6*7, 7*8, and 8*9 just for me, or for most people? And why?
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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 think that I get the answer because treadmills get set at 7.5 mph to get 8 minute miles. Maybe my answer should be “another math trick.”
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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 don't instantly know what 7*8 is, but I do know what 8*7 is.
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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?
I have a lot of anchor points in the times table memorized and 7*7 and 8*8 are two of them. I use them to get to the close by result quickly
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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?
8×8-8
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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 7*7=49 + 7= 56
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Mostly I have that one memorized. Otherwise, I decompose it into 5*8 + 2*8, which is 40 + 16.
@michael_w_busch @futurebird Yup, same. Alas, I don't have the full* table memorized these days, but I know enough to be dangerous and can 2-step my way to the answer.
* Did we all learn up to 12x12? That's how UK schools do/did it.
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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 4*14, maybe?
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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
Memorized, sure, but that particular product takes me a second to remember 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?
ohk im happy with the poll result, im also one of those that have some basic math thingies memorized and not really do any math to figure it out... phew!
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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 will admit to doing 7×7 in my head and then adding seven!
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@futurebird I did 7*7=49 then added 7, which means 1 less than 7+50 (because ending in 9), resulting in 56.
I did have the multiplication tables memorized in 3 & 4 grade, but I don't really much basic math on a daily basis, and if I do, I generally need to write it down so I can see it. I'm afraid that if I don't make a deliberate effort, I'll be innumerate.
28*2 or 50-14 probably.
Rote - instant recall - memorization of the entire table seems unnecessary to me… once the first half is in your head the rest is available quickly though doubling and adjacent addition/subtraction, but also, because human brains are very inconsistent at it. Personally, I think that flexibility of knowing how to connect relationships across categories and patterns is a huge part of learning to *think* mathematically.
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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 would say I don’t have it memorized. With the explanation given, I’ll probably use the other math fact that I have 2**n memorized a bit. So 8**2 = 64 then 64-8 = 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 I know my squares, so I do 7*7 and then add 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 when I was little I hated math and did everything to get out of doing any math. So I memorized the times tables, which I guess must have seemed easier? Anyway I remember being able to recite the correct answer quickly when it was just numbers, but being stumped when it was a word problem with apples or whatever.
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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?
When I forget my timestables:
7 * 10 = 70.
10-8 = 2.
2 * 7 = 14.
70-14 = 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 7×8 = 5×8 + 2×8 = (10×8)/2 + 2×8 = 80/2 + 8 + 8 = 40 + 16 = 56
easy
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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 remember learning my times tables as a kid. I still have the desk that I learned them at
Some of that has faded - for some reason I always stumble over results in the 40-60 range. So for this one (7*8) I would probably guess 56 or thereabouts, then check my work knowing that 8 squared is 64.
