# Talk

## 7 = ? - 9

(51 Posts)
PotteryLottery Fri 24-Jul-15 20:30:50

How would teachers explain how to work this out to a Y1 child ?

I don't want to confuse DD with my method.

SuffolkNWhat Fri 24-Jul-15 20:33:48

Count 7 on from 9

Fri 24-Jul-15 20:35:26

I struggle with this sort of thing. I usually ask ds to show me the methods he's learned.

FrizzyPig Fri 24-Jul-15 20:57:17

Firstly I would make sure the child understands the symbols and how to actually read the number sentence.

Then I would use a (age appropriate ) number line.

Explain that to get to 7, you've had to count back/ jump back 9.

I'd put something on 7 and ask how we could work out what number we started with... "Look we are on number 7, and we know that we've had to jump back 9 spaces to get here... What number did we start on?"

Let child figure it out.

Then discuss that 16-9= 7 is the same as 7=16-9 and why.

ReallyTired Sat 25-Jul-15 03:24:12

Lego is your friend. Get seven blocks of one colour and 9 blocks of another colour and out them together.

mrz Sat 25-Jul-15 07:20:20

I would have done lots of work on inverse operations over the year so child would be familiar with idea that if 7+9 =16 means that 16-9=7 (9+7=16/16-7=9) so can apply to find missing number

DoraGora Sat 25-Jul-15 09:24:21

I can't speak about teachers, but, the way I'd do it would be to sit my extended family around a long table and run a competition to find the most illogical way of asking any question about arithmetic. Then I'd find out where in the list the method above had been placed.

mrz Sat 25-Jul-15 10:20:43

You need to investigate which member of your family is making a secret recording to sell to the National Assessment authority and save the rest of us from your personal vice

Lurkedforever1 Sat 25-Jul-15 11:24:51

Haven't a clue how they teach it in school but I always taught dd to isolate the ? like an algebraic equation. We discussed balancing scales and then I remember having a demonstration involving toy cars and a blank piece of paper representing the ? with the = sign represented by two straight tracks off the toy garage. And then dd wheeled all the cars across the tracks till the paper was left alone, and counted up the cars. This game was apparently fun and we played many equations which then led to the point she translated it to a mental method.

SweetAndFullOfGrace Sat 25-Jul-15 11:29:12

The ? needs to be by itself on one side of the equal sign. Then the other side of the equal sign will tell you what the ? is.

Lurked' suggestion of scales is a good one because it's about balancing. So to "move" the -9 to the other side, you need to add 9 to both sides. You always need to add the same amount to both sides otherwise the balance wouldn't stay the same.

SurlyCue Sat 25-Jul-15 11:30:45

I would bring the 9 across the = which changes the sign. So 7+9=?

Sallyhasleftthebuilding Sat 25-Jul-15 11:37:25

This is a very difficult thing to teach y1 its always the biggest stumbling block. If u want to help look up numicon, get a set via amazon £30 and look up numicon.nz for ideas. You dont need the extras..

SweetAndFullOfGrace Sat 25-Jul-15 11:44:21

Or you could try something like cuisenaire rods?

poppy70 Sat 25-Jul-15 12:32:31

No no no. You do not isolate on one side of the equals sign anymore. Not even GCSE students do what... Although we all do it. This would be done as a counting on method on a number line and then rechecked by doing inverse.

SurlyCue Sat 25-Jul-15 12:35:20

No no no. You do not isolate on one side of the equals sign anymore. Not even GCSE students do what.

Ive just completed an adult access course which was initially GCSE followed by A level stuff. This is what we were taught. By a tutor who also teaches for GCSE alone.

Sallyhasleftthebuilding Sat 25-Jul-15 12:41:44

5 year olds just need to know that there are two numbers you use to find a third. 1+2= is finding a missing number .. they have the numbers they need. Same with 2+?=5 .. they have the numbers they need .. its what they do with them. The answer is irrelevant to the understanding of whats required... you teach method not outcome.

teacherwith2kids Sat 25-Jul-15 12:42:15

Like mrz, we would have done a lot of work on 'fact families' containing all the related facts using the same numbers.

So most children would simply recognise it as a member of the same fact family as 7+9=16 (or write out / talk through the whole fact family using ? - so ?-9=7, ?-7=9, 7+9=?, 9+7=? and discuss how we can use that to find out what ? must be).

If the whole fact family concept did not evoke a spark of recognition from your DD, Frizzy's number line method would be my next approach, combined with concrete objects to represent what I was doing on the number line if they got stuck.

RafaIsTheKingOfClay Sat 25-Jul-15 12:56:44

You can teach switching the side as a shortcut, providing that children also understand what is actually happening. There's no problem with that. It's much quicker and easier for simple calculations. I would recommend teaching either to 5 year olds though.

I would use knowledge of part/whole relationships and inverse calculations/writing families of number sentences. And I'd probably do a lot of work with solving similar problems in practical situations before just giving them a number sentence and expecting them to solve it. There's a huge amount of conceptual understanding that needs to happen first.

Lurkedforever1 Sat 25-Jul-15 13:03:40

poppy whilst I don't dispute that method works for many children or has its uses, it fails to work when you get to more complex equations. So at some point you need to learn to isolate. I did clarify my post by saying I haven't got a clue how they teach it in y1, so I clearly wasn't pushing it as the current recommended or only method, nor am I objecting to the fact number lines, counting on etc might be a better alternative for other children. I'm just sharing what I did.

mrz Sat 25-Jul-15 13:12:16

Lurked I do teach Y1 and would do it your way if child couldn't recall fact families

Pumpkinette Sat 25-Jul-15 13:19:33

I would say that one number on its own at either side of the = is the answer (ie 7) and the other numbers are the sum. If she didn't get it first time round I would switch it: ?-9=7

Once she figured it out I would get her to redo it as 7=?-9 and explain it's the same sum but just moved around. If I felt she still hadn't grasped the concept then I would do a few more examples for her using basic numbers ie: 4= ?-1 and get her to work them out. Once she has cracked it then go back to bigger numbers and longer sums.

That said my DD loves doing sums and is always asking for me to write some out for her to do. We haven't tried any like this so might put some in next time she is asking (she's going into primary 2 - y1 equivalent this year so if this is the type of thing they are teaching it's handy to know)

EmberRose Sat 25-Jul-15 13:22:37

I teach GCSE and A level maths... We teach them to isolate the x value on one side of the equal sign.

I think the key is some sort of real life object here with year 1 to demonstrate it- you need to move from concrete to abstract

SweetAndFullOfGrace Sat 25-Jul-15 13:35:54

Of course you have to teach isolating on one side of the equation. How else do you progress to proper mathematics? Ok, maybe you start at year 1 with numeracy as the main focus but it's also important for kids to understand the mathematical principles they're utilising.

Lurkedforever1 Sat 25-Jul-15 13:40:24

I'm not a teacher mrsz and when I did that method with dd I didn't even consider fact families or number lines, or indeed even think of equations or numbers in my head like that iyswim, even if I'd been familiar with modern primary teaching methods. I just explained how it goes in my head in a child appropriate way, and I expect for dd was the best way because she thinks similarly. Hence why all these different methods are all good because we do all think differently.

poppy70 Sat 25-Jul-15 13:58:07

Forgive me. I have seen balancing the sides but I don't see what I learnt anymore... Just manipulating numbers around the equals... As in jump over the equals and inverse the operation. Although presumably high level mathematicians do that automatically. Seriously though a Year 1 child should be taught to count on.

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