Do primary aged children need to learn the number bonds to 20?

[WhenTheDragonsCame]

I have 2 DC (years 3 and 1) and neither of them know the number bonds to 20. They could work it out on their fingers but can't do quick recall.

DD2(7) was slightly behind at the last parents evening but DD3(5) is supposedly very good at maths.

Should I be working with them to remember these at home or doesn't it really matter?

The ones which are IME, absolutely critical for future maths are:

Any 1 digit + 1 digit (so largest possible answer 18) - we discover weakneses in this all the time when it comes to column addition.

Teen number take away 1 digit, especially where it crosses 10 (so 14-5, but not so much 19-5) - again that becomes a block when they reach column subtraction.

However, that doesn't mean that all of them aren't valuable. When mentally bridging to e.g. do 24 + 8, they need to know instantly that 6 of the 8 will be required to make 30, but also that that will leave 2 extra, because 8-6 = 2. That's why it isn't just the bonds that make exactly 10 or 20 that must be learned.

mrz, that is good going!

I work with children who mostly have some difficulties with rote learning and retaining the facts in working memory (and often not a lot of support at home), so more like 2 weeks to learn each table, and for some it could be way longer than that! However, it great to see the difference it makes to confidence and ability to perform higher-level calculations.

Dragons, mainstream schools could so easily do the exact same practice with the whole class (each child at their own level) - clearly some do, but not all.

What's the method for teaching them properly wizard?

We do 'maths facts' practice 3x per week out of maths lessons (during registration) as well as at least 3x per week in Maths lessons.

It's cumulative building up over the year and over seven years so that by Y6 children should be able to complete 72 mixed questions in under 90 seconds (written).
We also do "nifty fifty" 50 times table questions in a minute (written).

Also remember with times table facts, the more you learn, the fewer there are to learn for each new table.

For example, 'Times table poster with a twist' halfway down this page www.kangaroomaths.com/kenny1.php shows the only facts you need to learn (once you now the 10x table) to know all times tables to 10x.

When we're teaching a new table, we always get the children to cross off the ones they already know, and so it is really common for children to actually speed up as they get to 'the difficult tables' rather than slow down.

Hi RafaIsTheKingOfClay,
I am not as rarified as many contributors, I can only tell you the little I know. I have taught my DDs, one of whom had hearing trouble, so could not benefit from songs etc over a two week period - after work.
Instant recall in any order with division facts secure at end of year1. One in year 2 now other in year 4 late july born. Can still recall all facts in any order.

In short, as I fell foul earlier of posting rules. If you had to teach 28 facts over a 2 week period, that would not appear a daunting task. That is all the tables can be reduced to.
Hope that sheds a little light.

We've reduced it to 36 addition facts and 36 multiplication facts so 72 facts by end of Y4

This game you can practice number bonds 10, 11...20.

www.mathplayground.com/number_bonds_II.html