KS1 maths advice - how to teach adding numbers up to 20 (bridging 10)

[breadandbutterfly]

My ds in year 2 has been given some quite hard sums (for him) -

eg 65 - = 27

or + 48 = 61

He has no idea how to do these and clearly hasn't been taught any methods (or if he was, he was not paying attention!)

Having tried to do the sums with him it is clear that the problem is that he isn't at all confident at adding or subtracting 2 numbers that bridge 10 eg he can confidently do 7 + 2 = 9 or 15 - 2 = 13 but not 7 + 8 = 15 or 15 - 8 = 7. So trying to add 17 + 8 or do 65 - 18 is just way too hard.

Plus of course he hasn't been taught how to find the missing number - but that's a step beyond so I'm not even worrying about that yet!

He can add quite big numbers in his head - up to 100 - but not confidently. Am wondering whether this is why teachers thought he could handle this? (Or may just because his teachers are a bit pants and are both part-time so both hope the other one will have covered the essentials?)

Anyway, could anyone suggest some resources to introduce/teach the concept and then lots of practice (pref computer games as he'll do those happily not as 'work' :) ) to get counting up to 20 really solid in his head?

And if anyone can suggest how to then apply that knowledge to adding/subtracting bigger numbers up to 100, that would be great too. :)

Thank you.

most of them get taught about countring on- so how much do you need to add to 48 to get 61
so you would do it on a number line

48 + 2 = 50, 50+10=60, 60+1 = 61

10+1+2 = 13

Thanks. :)

Any more ideas on resources etc?

Hi breadandbutterfly:

This was exactly where DD1 came unstuck:

Several solutions:

1. teach them units and tens and have them count with two different objects (raisins and grapes, raisins and smarties, buttons and legos, etc...)

Now have them try and add two two digit numbers together

say 23 + 36

Decide which is 10s and which is units (say grapes are tens and units are raisins).

On one plate have 2 grapes and 3 raisins and on the other plate have 3 grapes and 6 raisins.

Now have your DD count up grapes (2 + 3 = easy peasy = that's 5 - ah but grapes are tens - so can we count by ten - 10, 20 , 30 , 40 , 50. Let's write that down.

Now count up raisins (3 raisins + 6 raisins) - just count up = 9 raisins.

So what did we write down - ah yes 50 (and show her 5 grapes all on one plate) and then add on 9 raisins (9 raisins all on one plate) = fifty + nine = fifty-nine.

Now show her this writing it down.

It's up to you whether this is horizontal (which is how it will be done at school) or vertical. Oddly enough we avoided writing it vertically because the school was so dead against it - but in fact once DD was shown the vertical method (and drawing lines between to make columns) it just made a lot more sense. (highlighting the units also helps).

2. try playing 21. This sounds rather odd - but if you play it open handed at first as a family, it really helps with adding simple two digit and one digit numbers over ten. Same rules as ever - the goal is to get as close to 21 as possible or = 21 - but you lose if you go past it. You can spice it up by betting chocolates or biscuits - up to you.

Be sure to explain that all face cards are = 10 and the Ace = 1.

Deal two cards to each player - have your DD try and explain what it adds up to - say she gets a Jack and a 2 - so go through it slowly - Jack = 10 so what is 10 + 2 (hold ten in your head and count up 2 - say 10 - and then exaggerate counting up 11, 12).

3. play snakes and ladders - but have them add up in their head and then add another dice (so two die - adding up to 12). You can play it backwards (100 - 0) for practice with subtraction - if the game is going to fast play forward and back again.

4. Play with a deck of cards - face cards = 10 and Ace = 1 - just keep adding up to your target - say 100 - the one to reach the target wins. Or for subtraction start with 100 and keep subtracting. The one to read 0 wins.

5. SOME ON-LINE GAMES

Mumsnet has a link to mathschamp (off Learning/ Maths) - and they have good counting games here: www.mathschamps.co.uk/games5-7

BBC Bitesize number pyramid is good practice: www.bbc.co.uk/bitesize/ks1/maths/addition_and_subtraction/play/

Woodlands junior school has a good section on number skills: resources.woodlands-junior.kent.sch.uk/maths/numberskills.html

ICT games addition games are really helpful - some use a number line (catapault game) to help visualise what you're doing and may be a good starting point: www.ictgames.com/addition.htm

Anyway that's a start and I hope it helps.

Finally just to say that if you find maths a struggle and supporting it trying for both you and your DD, you may want to consider on-line tutorials - there's tons out there and all I can say is have an explore. Many here, myself included, have praised Mathsfactor (www.themathsfactor.com/, maths whizz (www.whizz.com/) and mathletics (www.mathletics.co.uk/) - all of these offer trials and many of us parents have found the video game formats a useful way of encouraging math practice at home, whilst making it a bit more interesting and removing the 'tension' of boring old Mum teaching these skills. I've personally found the visual approach seems to work a lot better than old fashioned pencil and paper.

HTH.

Does he have a Nintendo DS?

Math Training - like the more grown up Brain Training is really good for this. You can take a test every day too - get faster and better at it.

Wow, thank you esp PastSelByDate - really fab ideas esp love visual aids and card/board game ideas as trying to get ds to do more of these. Great links too.

Thanks for taking the time :) - shall print this page off for inspiration!