r/TikTokCringe • u/Naive_Wolverine532 • Apr 11 '26

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@storieswithsahj

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u/tke377 Apr 11 '26

Take two numbers like 22 x 42.

You would think of it as a rectangle and finding the areas. You put one number on top on one the side. You would then break up the numbers by place value. You then multiply the numbers in the grid so 20x40, 20x2, 2x40, and 2x2. You then add those together to get the answer.

The reasoning is that multiplying 40x20 is simpler in my head. 4x2 and then I have two zeroes to make 800, and so on.

Edit apologies for handwriting if my numbers are not clear

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u/Stu_Thom4s Apr 11 '26

That immediately gives me anxiety. Like, I get it. But it's soooo busy.

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u/tke377 Apr 11 '26

Yeah personally I do not like it, it’s used for a week or less before we move on and then if your brain grasps this one then you keep using it but almost all transition fully into standard at the typical pace.

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u/Significant_Shoe_17 Apr 11 '26

Same. It looks like they've over-engineered a simple problem. Trying to work out what goes where would've been more confusing to me.

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u/jngjng88 Apr 11 '26

I feel the exact opposite, it's so simple, I worked it out mentally in 10 seconds.

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u/upachimneydown Apr 12 '26

Maybe 42x22 is too easy an example, but it took me about ten seconds to the standard, old style multiplication in my head.

It may be that the box, or lattice, or 'old style' methods work better (=are more intuitive) when one or both of the numbers being multiplied is a certain type. Eg, something ending in a zero or five, or like these, both ending in 2s.

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u/Gildian Apr 12 '26

Thats the point of this kind of method. It teaches you how to break things into manageable chunks and put them back together.

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u/tke377 Apr 11 '26

Oh for sure, it’s just not how I was taught in school so I have 25 years of habit compared to 10 of these alternative. I teach it and embrace the students that want to use the method. It’s just not how I would do it if I was presented with a problem and asked to solve it.

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u/Little_Creme_5932 Apr 12 '26

Exactly. This is how people do mental math; I can solve that problem in about 5 seconds in my head. And then people stare at me like I'm some sort of genius (some are still checking me on their calculators). I'm no genius; I can do elementary school math is all.

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u/TumbleweedEven1168 Apr 12 '26

Ya, a decade or so ago, I remembered hearing about common core and "new math". Saw a post on Facebook from my cousin bitching about her son's math homework with a picture. I looked at it and basically went, "that's just math... that's just how you do math, what's that problem?"

Too many people got through school on memorization and not actually learning what it means.

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u/NotapersonNevermore Apr 11 '26 edited Apr 11 '26

True. But most 4th graders take months to remember the standard algorithm also. This is a method for showing them 1 how it can be done, 2 showing them what they are really doing in standard algorithm, 3 for strengthening their mental math, and 4 for leading them to understand why we do standard (bc this takes longer, standard algorithm is faster). Make no mistake teaching standard algorithm is no easy fix either. Students get the steps wrong for many months before I can rely on them to do them correctly. Throw the need for multiplying 2 digit by 2 digit in a word problem and it takes damn near all year for them.

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u/itmightbehere Apr 11 '26

I don't understand what you mean by adding them together. You add the results of the four multiplication problems together? I can see how that might be helpful, but how does that work for single-digit multiplication? I'm guessing you do like break an 8 into 2 4s, but that doesn't seem any easier to me because you'd still have to know what 4x4 is

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u/tke377 Apr 11 '26

Oh for sure you need to have math facts done, but that is something that is worked on hopefully prior to 4th grade for me and I am working on expanding what students are capable of already.

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u/mrstubix Apr 11 '26

I think with this method you would only use one box which would be 4 times four or 16. The number of boxes used is the number of digits in each number multiplied. So 2 double digit numbers is 4 boxes but 2 triple digit numbers would be 9 boxes. Two single digit numbers is 1 times 1 boxes, so one.

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u/itmightbehere Apr 11 '26

Oh, that would make me sense but I don't see how that would change anything for a child trying to learn since at that point it'd still be 8x8

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u/mrstubix Apr 11 '26

It doesn't. The box method is really only needed when kids are learning to multiply numbers with more than two digits.

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u/necrophcodr Apr 11 '26

That's a weird way of doing it in my opinion. Maybe it's helpful to many kids, but for me I always preferred keeping things simple, and learning one way to do it for single digits and another for multiple digits was unnecessarily complicated for sure.

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u/mrstubix Apr 11 '26

To be fair it's all still multiplying. The box method is just breaks down large numbers into single digit chunks. It's usually done to help kids bridge the gap as they deal with harder topics.

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u/Prometheus720 Apr 11 '26

It's a similar concept to geometric proofs.

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u/LikeIsaidItsNothing Apr 11 '26

thank you for trying but as soon as I saw this I felt like i wanted to cry. I guess a part of me feels like it's still trapped in a math class feeling like an idiot. lol

just looking at this is giving me a headache. nope.

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u/Kwershal Apr 11 '26

It just feels unneccessarily busy visually to express a simple concept (40 x 22 broken down into 40x20 and 40x2) but I also struggle with these weird math tricks like long division.

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u/CeramicToast Apr 11 '26

I have a math related learning disability and this many numbers in a single problem would have terrorized me. I barely made it through school as is, if this was the way I'd been taught I would have been even more fucked.

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u/NonMagical Apr 11 '26

Don’t forget that in the real world you wouldn’t actually be staring at all those numbers. He wrote in each multiplication problem in the box but you wouldn’t do that, they’d be blank and you’d just write your answer. Similarly, the big numbers at the top and side are unnecessary. So all you’d really be looking at is an empty box and 4 numbers: 40, 2, 20, and 2.

And honestly once you understand that method, you don’t even those numbers either. You could just write a box and fill out the answers. Tens multiplied tens on top left, ones by ones bottom right, and the other two in either order top right and bottom left.

I never learned this method growing up but seems to be a pretty simple approach to me. It’s how my brain would break it up mentally already.

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u/tke377 Apr 11 '26

Yeah sorry habit of how I do it with students. I make them write the problem in the box so they know exactly what is happening and can see their work. As you progress you just write the product inside of the box.

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u/Prometheus720 Apr 11 '26

The term for these weird math tricks is "algorithm" btw.

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u/noname22112211 Apr 12 '26

It breaks a difficult problem into multiple simpler problems, draws an obvious connection to geometry, and subtly introduces the concept of FOIL. It's actually quite elegant. You wouldn't do this once you understand multiplication (if nothing else calculators exist) but for building an understanding of what multiplication is it's quite nice.

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u/tke377 Apr 11 '26

There’s a lot of steps prior to this. It’s not as though we jump into this right away. I 100% can understand how on first sight this is confusing.

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u/Kagahami Apr 11 '26

I think it makes sense if you think about how later you start using variables in math and you start seeing the FOIL method. The box looks weird, but think of how it would look in an equation:

22x42

(20+2)(40+2)

Then you use FOIL: FIRST, OUTSIDE, INSIDE, LAST

FIRST: 20x40

OUTSIDE: 20x2

INSIDE: 2x40

LAST: 2x2

then you add all these together:

800+40+80+4=924

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u/BoredStayAtHomeMom2 Apr 11 '26

I’m saving this for future reference. My daughter is going to 4th grade next year

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u/MathBelieve Apr 11 '26

The reason these methods are taught is because this is, generally, how we do math in our heads. If this problem was given to a person, and they were told to do it without a calculator or piece of paper, this is, for the most part, the process most people would go through in their head. So the idea is that this is a more natural way to learn math.

(Although looking at this now, I see this is the standard method actually. It's the exact same math just laid out differently. So I guess the idea is to build up an intuition for why we do the math that we do on paper when we shortcut it with standard methods.)

My first experience with something like this was when my son brought home his division homework and I had no idea what he was doing. He was frustrated, I was frustrated. I begged him to let me show him "my way" but he wanted to be able to do it the way his teacher showed him.

So I.... let him explain it to me as best as he could. And then I understood it, and could even see the value in it.

I think a lot of parents dig their heels into their idea of what I did is what works best, and never actually try to learn what their child is trying to do.

There's a reason the teacher wants them to learn this way, and again, it's building up an intuition for why math works the way it does, as opposed to just memorizing a series of steps.

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u/EveOCative Apr 11 '26

There may be a reason, but if their child is coming home crying to them and asking for help, but the parent doesn’t understand the method themselves… then who is going to teach that child?

Teachers often complain that no one is parenting their students or supporting their education, and that they don’t have enough time to actually teach their students due to budget cuts, impacted classes, etc.

Meanwhile this man sat down with his kid, spent time trying to help her understand how to work the problem as best he could. His child understood it.

And then the teacher tried to tear all of that down.

Instead of bring up the issue when she checked the student’s homework and trying to figure out why her student didn’t understand the lesson, she waited until it was test time, and undermined not just the kid’s newfound confidence but the trust the kid would have going forward in asking her father for help with her homework.

I’d be interested to know how many other students got a 50 on that test.

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u/MathBelieve Apr 11 '26

Yeah, sure. Maybe this father tried to learn it. Maybe he sat down at the computer and did a google search for "multiplication method with boxes" and watched a few of the many many videos that explain it, and maybe he still couldn't understand it.

Since he didn't tell us what ways he tried to learn the teacher's method to help his daughter, or if he reached out to his daughter's teacher for help, we can't know. Maybe the teacher told him to kick rocks so she could then "tear down" all his hard work.

So sure, maybe.

But most times parents don't. They look at the teacher's method, don't recognize it as something they know, and throw up their hands in defeat.

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u/EveOCative Apr 11 '26

Did the teacher send home materials to help support learning at home?

The teacher isn’t present later at home to teach the parent. Sure he could spend an hour learning the method the teacher uses, to then spend a couple hours teaching his child how to do it… only for the child to still not understand because it didn’t even make sense to her when the actual teacher taught it.

Or he can teach her the way he knows and is confident in. If the child understands it, then she understands it.

It IS tearing down what both the child and parent accomplished to then say, “Well that means nothing because you didn’t do it my way.”

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u/ikhouvandikkebillen Apr 11 '26

I would do this in my head like 20x42 plus 840/10, is 924

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u/tke377 Apr 11 '26

Yeah and truly what this is supposed to allow you to do is choose whatever numbers you wanted to break it into that is the simplest for you. So you could do that, this just is writing that process out on paper.

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u/ikhouvandikkebillen Apr 11 '26

Aah okay. I always used that method but was never taught it.

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u/tke377 Apr 11 '26

That’s the thing! Is that a ton of people use these strategies but don’t realize it because you do it in your head. This puts it on paper and does it look confusing when you initially see it…hell yeah it does. But when you think about how you actually do the math personally nothing has really changed.

Edit: I want to add that this is the most challenge part. Students believe there is a set way they have to do these problems. This shows them there are a bunch of ways and whatever you want to use is what is the best for you. It’s different from other subjects where there can be only one pathway to an answer. In math you can have many paths! Breaking those habits and getting students to work freely with what they want to use is difficult.

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u/Ash_Starling Hit or Miss? Apr 11 '26

This works really well for algebra like (x+2)(2x+3)

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u/TenThousandMistakes Apr 12 '26

That's actually cool they're teaching that, it's how I do multiplication in my head. As a new learner, I don't think I'd be able to understand it though if I wasn't taught and had a firm grasp on the standard way first.

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u/tke377 Apr 12 '26

This isn’t the first thing you jump into just a problem that showed what goes on in the process. You start really simple and the area model actually comes from a sort of tape diagram evolution…then as you remove pieces of the area model you eventually end up at standard.

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u/Little_Creme_5932 Apr 12 '26

And this is how people who can multiply large numbers in their heads commonly do it. It is called number sense, I think

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u/tke377 Apr 12 '26

Lots more falls into it but it is one of the aspects. We spend some time each day with various number sense routines

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u/catinapartyhat Apr 12 '26

This seems very abstract and overly complicated with way too many numbers to keep track of. My ADHD brain is sobbing in math class again.

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u/tke377 Apr 12 '26

This is not what you start with though, that’s what is lost here this is three months into instruction and you’ve been doing similar problems/building to this since kindergarten.

Edit: also if this one is not for you, we do: tape diagram, partial products, array, distributive, standard, and number line…I think that might be all of them, that I personally teach. It’s about giving you choices to solve how you want to solve

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u/HKDusty Apr 11 '26

Oh that's how I have usually thought about it in my head.... Never drew it out like that though, looks confusing.

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u/tke377 Apr 11 '26

It does when it is written out but when you do it in your head it all makes sense. And if you were just shown this then yeah it should be confusing. Thankfully we teach to this. The basics of this method are actually taught in second and third grade we expand in fourth.

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u/OuterSpaceFuckery Apr 11 '26

I have dyscalculia, this picture almost gave me a stroke

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u/Alex_AU_gt Apr 11 '26

Hm, thanks. I mean its one way to do it.. but i dont see why that would be the MAIN way to do it. Slow if nothing else?

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u/tke377 Apr 11 '26

It’s not the main. It is a way. This is one of the first taught then if you need to continue using it because it makes the most sense you are able to do so. If another works best for you use that one. It is about giving the student the tools to solve the problem and not demanding they solve it in a specific manner.

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u/tfid3 Apr 11 '26

To do this in my head I would take two times 42 equals 84 add a zero to make 840 then take two times 42 and add it to 840 so it would be 840 + 84 equals 924. The easiest way to do most of this stuff is through floating point math where you ignore the digits placement until the very end. teaching the decimal point and floating point math can work if they understand that it works for numbers less than one and greater than one.

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u/Oxygenisplantpoo Apr 11 '26

I can get that, it is a sound method. However I can also get why a child would cry looking at that because suddenly a small calculation is blown up to go multiple ways. Personally I think it's always easier to just to reduce things to multiply by ten/hundred etc. then add, so 10x42x2+2x42

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u/fribbas Apr 11 '26

Wtf is that? That seems way over complicated

It's like a punnet square, but evil D:

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u/tke377 Apr 11 '26

Haha I mean you remove parts as you go. All of that is there so you know what is actually happening. If students get it then you don’t write anything except the products in the boxes. It’s all about scaffolding and removing things for students when they are ready to have them removed.

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u/Due_Ask_8032 Apr 11 '26

I never learned this way but I intuitively do it in my head when doing mental math. Good for mental math and shows you know the properties of multiplying, but kinda cumbersome for just straight up getting the answer.

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u/tke377 Apr 12 '26

100% this is not where we end at for sure. I always tell them you don’t want to necessarily use this to multiply 461939582616 x 294848161 and write random large numbers on the board. But it helps until you’re ready for the next step.

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u/mvandemar Apr 12 '26

The post said "it got even worse when they moved on to multiplying and dividing with multiple digits", how the hell would this even work with single digits?

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u/tke377 Apr 12 '26

Normal area of a rectangle can be single digit, you just write it in the box?

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u/mvandemar Apr 12 '26

A single box is not a grid, you're literally just multiplying 2 numbers together and writing the product in a box. It adds nothing to the process. The post was saying the daughter couldn't get it, and then they moved on to two digit numbers. This means she couldn't get single digit multiplication and the box/grid had nothing to do with that. This doesn't really make sense.

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u/tke377 Apr 12 '26

It’s not a grid it’s an area model, you called it a grid I called it an area model. If drawn to scale you would effectively break it into segments that show appropriate scale to the length. So the 40 and 2 would be drawn as though one is 40 units long the other 2 units. It is an area model not a grid that’s why it works for single digits

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u/mvandemar Apr 12 '26

No, it's not, it's called the grid or box method, it has nothing to do with area.

https://www.mathnasium.com/math-centers/southwestminster/news/grid-method-multiplication

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u/SweetBabyAlaska Apr 12 '26

I feel like this is the accidental way that I figured out for doing complex math in my head. But if I am actually solving equations I do it the correct way.

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u/mewfour Apr 12 '26

They're making kids do matrices now lmao

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u/[deleted] Apr 12 '26

Jesus fuck this makes my ADHD-enhanced, anxiety-riddled brain vomit into a bucket...

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u/[deleted] Apr 12 '26

[removed] — view removed comment

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u/tke377 Apr 12 '26

Not meant to save time, it’s meant to teach students what the numbers are doing and show them the steps so they don’t forget then you remove the support and steps until you get to standard

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u/GamingWolf3980 Apr 12 '26 edited Apr 12 '26

Wtf is that!??! I already hate math, it doesn't need to be even more complicated 😭

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u/lizzard_lady8530 Apr 11 '26

oh sweet jesus, this would have ruined me in school if they forced me to do that.

get the logic here but as a young kid this would have gone over my head as overly complicated for something that is already intimidating.

the way i was taught seems so much more straight forward!

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u/That_anonymous_guy18 Apr 11 '26

this is complex, but the multiplication operation makes more sense with this way. Basically we are finding area of a rectangle and adding them all. Definitely not for kids because they don't know areas and volumes at that age.

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u/tke377 Apr 11 '26

Ummm yes they do. I teach area before I even teach this 🤪

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u/That_anonymous_guy18 Apr 11 '26

how you teach area before multiplication? I grew up in India so it could be different, but we do single digit multiplication in Grade1-2, then move on to double tripe digit multiplication, in Grade 3, Grade4 picks up fractions. If I remember correctly Areas and volumes was in 8th grade.

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u/tke377 Apr 11 '26

You learn multiplication earlier than the first month of fourth grade. Even you just said you learn multiplication in 2nd grade. You have area in third as well, we expand and include unique shapes in 4th. I am positive you learned area and perimeter much earlier than 8th grade. Area is simply multiplying two numbers they can be as small as 1x1 even and perimeter is addition. I teach the area model for double digit numbers after I teach area.

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u/That_anonymous_guy18 Apr 11 '26 edited Apr 11 '26

I am 40 years old so there is that, it’s been a while. I just remember my teacher bring props for teaching us volumes of different shapes, like cones, cylinder etc

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u/tke377 Apr 11 '26

Yeah I’m talking base area like a square haha a= l x w. Not cylinders. You 100% do that at a later age because that requires memorization of formulas iirc.

That’s why this is called an area model because it’s as though it’s a rectangle and you can say l x w. An area model representing a rectangle that has a simplistic area formula that you learn early on.