KS1 maths methods

[Monkeymonstermum]

56-32

What method should a KS1 child be using for this? I know how I would work it out...but DS can’t tell me how he’s supposed to. He’s fairly good at maths so a lot of the time is coming up with the correct answers to maths questions but often doesn’t know why. He’s struggling with this and can’t tell me how he’s supposed to do it.

Does anyone have a summary of methods they’re supposed to use for different questions (or is it different in each school)?

See if your school has published their calculations policy or search for your county's calculations policy. That should give you a visual demo as well as explanation of methods taught at each stage.

Off the top of my head I'd say he should be demonstrating on a number line but I'm a bit out of date.

What year is he in? Depends what he learned and what he's secure in. There are different methods.. number lines, tens and ones, column method and some children do it mentally.

Is this for homework? Then it should probably be whatever method they are doing this week.

Year 2

Year 2 teacher here, I would teach this in 2 ways. 1. Partition numbers into 10s and 1s, do 50 - 30 then 6 - 2 then recombine the 20 and 4. 2. Numberline, put 56 on the number line, subtract 3 tens to take it to 26 then subtract 2 ones to 24, in this one you're only partitioning the second number.

User...thank you

Eventually got out of him he should use number line...except I think he usually does it in his head so when he gets more difficult ones he’s just guessing...

I can’t remember ever doing number lines. He’s (eventually..like pulling teeth) takes numbers away on the bottom to get to 32 and they added them up. Seems v convoluted to me....

Oh I see, yes that is another way of doing it I guess, if you think of subtraction as being more 'find the difference' rather than 'taking away. I would personally always introduce it as I explained above and then later look at it as your son has done it there. The number line is a way of him explaining his thinking, and really important because - as you're discovering with him - otherwise those children who pick things up quite quickly can do the more simple calculations mentally but without really understanding the structure of what they're doing, so they know 'how' but not 'why, and as you said that then creates problems when later they come to trickier problems. I will often ask pupils to draw pictures or a number line to prove their answer is correct to me so they have to think about how they solved it.

Hmm, yes, I think you’re right about the ‘how’ not ‘why’. The teacher thinks he’s over confident and that’s why he occasionally gets things wrong but most of the time does v well but I wonder if he actually doesn’t ‘get it’ as often as she thinks he does. We’ve never done much outside school (aside from the set homework, which isn’t much) but I’m now wondering if we need to make sure he’s got a few more of the concepts embedded.

That's really common in children who get the hang of a lot of maths quickly, they usually cope really well in KS1 but often come unstuck in KS2 when they have to apply that learning in different contexts. In my experience a bit of extra help at home never hurts. He's lucky to have a parent who wants to help , good luck with it.

DD1 in year 2 would use a variation on the column method to do this (basically they've tweaked how they've set it out a bit). She's fairly confident with the school's teaching of the column method though (the kid annoyingly dead on the borderline with expected and greater depth and no one can quite work out which way she'll end up!).

It has taken a good few months to stop her from trying to waste the entire lesson drawing out 56 beautiful dots, losing count repeatedly and having to start again and then crossing out 32 of them after sharpening her pencil or changing her whiteboard pen 96 times during the whole of the ruddy lesson though (DD1 can be a master procrastinator... it's genetic!)

So is there anywhere online I can look to see these ‘methods’ to be able to explain them? I know how I do things but I don’t want to explain ways he shouldn’t use. I sometimes don’t ‘get’ the fact that he doesn’t ‘get it’ and then I become frustrated!!

Please accept my apologies if I am out of order asking this, but how the hell is all that faff about lines etc beneficial?

I know I'm probably wrong but really cannot get my head around how that is easier than the way (back in the day!) we were taught.

This is a genuine question. I was a TA for years - luckily for the children they were in nursery! The maths always put me off 'helping' older children.

Thank you

I taught my dc the column method, as she was trying to use her fingers an toes. The teacher subsequently told me this is not the done thing in maths these days.

Unfortunately now my dc has decided they prefer to do sums the column method than drawing sticks and dots for tens and ones.

Surely at some point kids are going to stop using number lines and drawing tens and ones? What is so bad about the column method?

I thought that they were “supposed” to do this by partioning. Ie 56 is 50 and 6, 32 is 30 and 2
50-30 =20
6-2=4
20+4=24
Etc

Then they do column addition/subtraction in ks2. That way they learn several ways to do it and can eventually chose what works best for them?

I looked this up in the NC recently as my dc’s teacher had set it as homework before beginning it in class and I had no idea what method to show dc.

Guardsman, I agree. I learned Hundreds Tens and Units and borrow the ten, and all the more modern methods I read about seem far more complicated.

50-30 =20
6-2=4
20+4=24

How does that method work if the sum is 56-29?

I know @Anna!

Sorry - I meant that I could do it my way! I am really baffled how anyone can think the old way isn't a simpler way

DD1 started out breaking the numbers down into 10 sticks and 1 bricks - so 56=50+6... then setting them out as

Tens Ones
50 6
30 2

And now does pretty much standard column subtraction but they draw a grid to do the tens and ones into to help keep it separate. That's been the rough progression over the course of year2 for her.

Hopefully that makes sense via the dodgy formatting.

By the time students it's easy to see the students who have been taught "methods" such as borrowing tens and those who have learnt different methods and therefore understand why.

Please don't just use methods which usually involving incorrect language as "carry the one" but do try and demonstrate methods such as partitioning as it proves understanding that you are crossing over tens and why it works.

Oops didn't proof read. * By the time they get to secondary school.

By the time students it's easy to see the students who have been taught "methods" such as borrowing tens and those who have learnt different methods and therefore understand why.

Er - I understood perfectly well what I was doing and why using the methods I was taught.

*Please accept my apologies if I am out of order asking this, but how the hell is all that faff about lines etc beneficial?

I know I'm probably wrong but really cannot get my head around how that is easier than the way (back in the day!) we were taught*

There are lots of people who know the old methods for doing calculations but have very poor understanding of maths in general because they can’t tell you why the method works. If you understand how to manipulate the numbers then you can do the inverse calculations and all kinds of problem solving that you can’t do as easily if all you learned was how to do the calculation without knowing why you did it.

Thank you @Paquita. That does make sense. My maths is appalling, my son is very good at it but I couldn't begin to help him in any way.

Do you think that suits every child though? I hope you don't think I'm being rude, but would you mind explaining why? It just seems to me that the method used only helps the children who are very good in maths anyway.

DS is not "very good" in maths - below expectations with age as with everything else. But the numberline stuff helps him to think through what he's doing slowly enough for him to get it.

Ok. This is really interesting to me. I was just interested in why the new way was better than the old way.

56 - 29

I suppose it could work as:
50-20
6-9 (cant do this so we borrow from the 50 above)

So
40-20 = 20
16-9 = 7

20+7 = 27