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# Multiplication tables - what you learned, what your dc learn

• 9 x 9
38
• 12 x 12
92
• 16 x 16
1
• 20 x 20
3
• Other
19

• 9 x 9
21
• 12 x 12
101
• 16 x 16
4
• 20 x 20
4
• Other
27

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Hi everyone,

When speaking with others, I'm surprised at the variation in what was taught for the multiplication/times table. It seems my parents learned more (16 x 16) than I did (12 x 12), whereas an Indian friend claims they learned up to 20 x 20.

More is not necessarily better - I think the Chinese teach up to 9 x 9 and they are generally quick at computation. On the other hand, I can see the utility of knowing 12 x 12 or 16 x 16, e.g. under the imperial system of 1 ft = 12 inches, 1 lb = 16 oz.

So here is an informal poll: what did you learn, and what are you teaching your dc? If you want to give any background info, e.g. what your parents learned, which table(s) you've used the most, please feel free to do so!

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I am pretty sure that I learned the tens, just because they're so easy. I don't think I did much with my son after 9, but he taught himself his 11s. I confirmed with him that he knows up to 11x11, and he says he knows 12x12 and some of the 12s. I have never observed needing to know more than the first few of the 12s, enough to, say, easily convert between inches and feet and inches for up to 6 feet tall. I can't think of a time I've used 16s in particular.

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I am pretty sure that I learned the tens, just because they're so easy. I don't think I did much with my son after 9, but he taught himself his 11s. I confirmed with him that he knows up to 11x11, and he says he knows 12x12 and some of the 12s. I have never observed needing to know more than the first few of the 12s, enough to, say, easily convert between inches and feet and inches for up to 6 feet tall. I can't think of a time I've used 16s in particular.

Yes, I debated about putting 10 x 10 into the poll options but ultimately left it off. Neat that your son taught himself additional tables!

Come to think of it, I don't usually convert much between lbs <-> oz and feet <-> inches. When buying furniture, the measurements are all in inches rather than feet and inches. I do tell my dc their height in feet/inches but mentally I remember it as m/cm and then convert it to ft/inches if the person asking is American.

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I voted other for me because I was thinking it was definitely 10x10 I learned up to. My kids are definitely getting up to 12x12 both in their math curriculum and in various math fact games we play.

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For those who chose Other, I'm curious - what option did I miss?

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9x9 was what I learned and my expectation for my DCs. However, we do squares up to 25

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I learned up to 10 x 10.

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Another 10 x 10 for me and 12 x 12 for the kids. They didn't appreciate it at all :).

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I marked that we covered 12x12 when learning the multiplication tables with my son but that he can multiply 2 digit numbers in his head using mental math skills. Something times 20 is just double of times 10 so no need to memorize it IMO. He can use the same trick to solve multiplication questions for pretty much any combo of numbers. 27x11 is just (11x10x2)+(11x7). We did 12x12 because all of the materials we bought did.

When I was in school I went to lots of different schools (we moved like a seed pod) but pretty much everyone was teaching up to 10x10 but since 10s times tables are a no brainer, I marked 9x9.

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I learned 10x10 in elementary and then moved to a district that had learned 12x12. I had to work hard in 5th or 6th grade to pick it up, since there was still some amount of drill occurring. I still only know up to 6x12 easily and count up by 12s after that until I reach 12x10. Our math curriculum only teaches 10x10s. I've taught the trick for 11, but we haven't done much with 12s until we stop struggling through the rest.

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We learned 10x10, all squares up to 20x20, all cubes up to 10x10x10.

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We learned to 12x12.

We learned 10x10, all squares up to 20x20, all cubes up to 10x10x10.

This is what I'm having the kids do, as well as primes through 200 and powers of 2 through 2^12 (just by doubling, with the two touchstones 2^5 is 32 and 2^10 is 1024).

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For those who chose Other, I'm curious - what option did I miss?

I really didn't memorize the times tables. I'd derive them by addition more often. It's slowed me down. My son has through 12s memorized. I will want him to have cubes through 10s memorized as well, although I haven't pushed that yet.

He does have quite a few powers of 2 memorized due to MineCraft :)

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I chose other because my dd is learning through 15x15 because it is required by Classical Conversations. This will probably be true for other CC families. I learned through the 12x12 in school. I think that is/was fairly standard.

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This is what I'm having the kids do, as well as primes through 200 and powers of 2 through 2^12 (just by doubling, with the two touchstones 2^5 is 32 and 2^10 is 1024).

I'm intrigued - primes and binary arithmetic! For the latter, your dc will enjoy Computer Science. Are you learning primes out of interest in number theory?

I really didn't memorize the times tables. I'd derive them by addition more often. It's slowed me down.

I've met someone who did that (key facts + addition) and who claims that it was easier that way vs. memorizing. It was hard for me to comprehend, but then again he did well in college.

I chose other because my dd is learning through 15x15 because it is required by Classical Conversations. This will probably be true for other CC families. I learned through the 12x12 in school. I think that is/was fairly standard.

Ah, yes, CC! I believe they teach them as skip counting, and also introduce the squares to 15 x 15, and cubes to 10 x 10 x 10.

Thanks for the responses, everyone! It has been interesting to understand why we do things a certain way. Most of the times we go with something because that's what our math curriculum teaches, but there are clearly decisions to be made in the tradeoff (spend time drilling now vs. time computing later).

Squares and cubes are an interesting aspect too - I didn't memorize any, my parents did. I hate to sound utilitarian, but when are they most useful - approximation of area/volume? Trig? I don't remember using them, although for trig and EE classes the square roots of 2 and 3 popped up so much, I knew their approximations by the end of the term.

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I learned 12x12, and I'm teaching the girls 12x12. The twelves are important to memorize: besides inches to feet, you need to be able to calculate dozens when shopping. The schools around here only teach through x10 and it mildly annoys me. I mean, if you're going to go that far, might as well go all the way to the dozens.

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I learnt up to 12x12 and I put that for the kids because I assume (possibly quite wrongly) that they will need to learn that at some point at school. Initially I plan to teach up to 10x10 because I have a puzzle that goes to 9x9 and I think he already known the 10s.

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I learned up to 12 x 12. Ds learned up to 11 x 11 and then some of the 12â€™s. I didnâ€™t drill the 12â€™s as much as the others. He also knows some bigger numbers that are useful like 15 x 15.

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I learned up to 12 x 12. all my children's' books only go up to 10 x 10. but I have them do the 11's just because they are so easy. My mother learned up to 16's. I am guessing she had to do up to 16's because they used imperial measurements when she was a child, and they only teach up to 10's now because everyone here uses metric.

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I learned to 12 times 12. Dd has only learned to 10x10, but she's young, so we may get further at some time.

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I learned up to 12x12. Planning to teach my kids up to 15x15 because there have been many times that I have needed them and wished I had them memorised.

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I learned up to 12 x 12. The kids are learning up to 15x15. They are also learning squares to 15 and cubes to 10.

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Up to 11 x 10 at least. The 12s a bit, but not so much. Up to 10 x 10 seems needed, but the 11's up to 99 are so easy, why not?

12s seem useful even if doing metric because it helps with hours in a day as well as dozens and inches in feet, but I have not stressed the 12s. I've not found myself wishing I knew any beyond the 12s. But if it becomes needed higher, it could be learned to whatever point is needed.

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I learned up to 10s, both dss up to 12s. However, 11s and 12s are easily done quickly in the head, so no real need to memorize.

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We were taught 10 x 10, but I learned 11 x 11. That's what I'd expect my children to do as well.

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I think I did up to 10*10, but I was supposed to go to 12*12. I am going to learn up to 15*15, squares up to 20, and cubes up to 10, just for fun and novelty sake.

I will probably teach my kids up to 15, but to be fair you don't have to 'learn' 0 tables or 1 tables and 10s are effortless and 2's are really easy too, so they'd only be learning 12 tables, as if they'd learned up to 12*12. ;p

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I think I remember having use mulitpilcation in school. I don't even remember being taught them.

:laugh:

I have taught up to 12. That is how high Timez Attack goes.

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I chose other because I never learned them. Well, eventually I picked most of them up, but I was never formally taught. We moved from one school to another and in the first school, we weren't to times tables yet, and at the second, they had already covered them. I still have trouble with my 6, 7, and 8s.

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I learned up to 15x15, but my kids will learn up to 12x12.

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12 x 12 plus squares to 20, then key squares ( like 25).

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12 x 12 plus squares to 20, then key squares ( like 25).

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Hubby and I learn up to 12 x 12 in school by first grade. I learn up to 16 x 16 for fun. My kids are supposed to learn up to 9 x 9 in public school. They taught themselves to 12 x 12. My parents had to learn up to 16 x 16 during the British era in the 1940s (Asia).

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I chose other because I never learned them. Well, eventually I picked most of them up, but I was never formally taught. We moved from one school to another and in the first school, we weren't to times tables yet, and at the second, they had already covered them. I still have trouble with my 6, 7, and 8s.

Ouch. I have heard of similar experiences - I understand why kids here (US) might be nervous about moving to a different school.

12s seem useful even if doing metric because it helps with hours in a day as well as dozens and inches in feet, but I have not stressed the 12s. I've not found myself wishing I knew any beyond the 12s. But if it becomes needed higher, it could be learned to whatever point is needed.

Good point about 12s being useful for base 12/base 60 measurements. Your post also reminded me of another point - are there some languages which express their numbers in a different base? Doesn't French, for example, express 60 as 3-20? I'll vouch for Chinese being consistent in using base-10 (which is why they have a mnemonic for the tables to 9x9).

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Ouch. I have heard of similar experiences - I understand why kids here (US) might be nervous about moving to a different school.

Good point about 12s being useful for base 12/base 60 measurements. Your post also reminded me of another point - are there some languages which express their numbers in a different base? Doesn't French, for example, express 60 as 3-20? I'll vouch for Chinese being consistent in using base-10 (which is why they have a mnemonic for the tables to 9x9).

Sixty is soixante, but 80 is quatre vingts (4 20s), and 99 is quatre vingt dix neuf (4 20s 19).

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I learned up to 11x11. We simply ran out of time before I got to 12's (I was the most advanced in the class).

I am teaching to 12x12 and will cover 15 facts. Far too often I have to stop and think or pull out a calculator to convert inches to feet and I regret not beng fluent.

I was never taught squares or cubes.

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I learned up to 12x12.

For what the children learn, I used the class I taught this past year as my "child". I formally taught them up to 9x9, but we did enough games and stuff that many of them (my high and mid-high learners) learned up to 12x12 as well.

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Though in Belgium, the French speakers say huitiante for 80 and nonante for 90.

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I've taught to 12x12. Anything above that is easily calculated if needed. Why bother memorizing how to multiply by 15 if you can multiply by 10 and add half that to itself? That's how I figure out a 15% tip at a restaurant. I have rarely needed to multiply by 13 or 14 mentally, though I do remember 13^2=169.

I think memorizing up to 9x9 is most important, as that's what you'll need for multi-digit multiplication. 10s and 11s are dead easy. 12s are useful for daily life due to time and the use of "dozens" in retail. If you need to multiply 8x14, you can just do 80+32=112. Easy peasy.

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I've taught to 12x12. Anything above that is easily calculated if needed. Why bother memorizing how to multiply by 15 if you can multiply by 10 and add half that to itself? That's how I figure out a 15% tip at a restaurant. I have rarely needed to multiply by 13 or 14 mentally, though I do remember 13^2=169.

I think memorizing up to 9x9 is most important, as that's what you'll need for multi-digit multiplication. 10s and 11s are dead easy. 12s are useful for daily life due to time and the use of "dozens" in retail. If you need to multiply 8x14, you can just do 80+32=112. Easy peasy.

I was never taught to do that kind of mental math. That trick you did with 8x14 is a completely foreign way of thinking for me. I'm guessing I'm not the only one! ;) Thankfully my dc will learn differently and it will hopefully come more natural to them.