How do they teach addition to 100 these days?

[SlightlyMadSlug]

I remember adding the columns and carrying the 1(or whatever) - but I vaguely remember a thread previously saying that this was no longer the case.

DTDs (6) have been learning their 'number bonds'. They have done number bonds to 5, 10 and 20. Now they are learning their number bonds to 100. First of all they need to learn the 10's (i.e. 10+90, 20+80, 30+70 etc.) but they getting there with those and need to start learning all the ones in between (i.e. 12+88, 65+35 etc.) How is this taught in primary schoolds today?

Anyone? Can't find it on archives cos I can't remember what it was 'called'

It used to be called hundreds, tens and units - does that help?

Erm - thats what I thought - but I din't thin they taught adding the columns any more. Maybe I'm imagining it. I just don't want to teach them my way and then they have to relearn it IYSWIM.

I don't know what they do now I'm afraid, but I can't understand why they'd change it. The old system works just fine if I remember correctly.

I thought it was something about learning why the answer is what it is and not just how to do it.

Have been doing a bit more searching. I think it may be called partitioning, will have a proper look tomorrow and hope someone can come and tell me an easy way to teach number bonds to 100.

As you've said, they initially learn their number bonds to ten ie:
1+9 or 9+1
2+8 or 8+2
3+7 or 7+3
4+6 or 6+4
5+5

They use number lines to add simple numbers:

7+2+?

On their number line, they put their finger on 7 and jump forward two places to land on the 9 (hope that's clear!)

From their number bonds to ten, they then work out that if 1+9=10 then 10+90=100 etc

To add two digit numbers, they do this by partitioning and chunking:

58+22=?
50+20+70 (know this from number bonds above)
8+2=10 (as above too!)
70+10=80

Adding two digit and single digit numbers is then a matter of mental practice/
Hope that helps. Wait 'til you get to long division , new style!

should have read 50+20=70 above!

I think they split out double digit number so
58 becomes 50+8
and 22 20+2

2+8=10
50+20=70

10+70=80