# Talk

## 13, 14, 15 times tables - required for KS2?

(14 Posts)
Snowlike Wed 23-Oct-13 09:07:02

Is it necessary to learn these once you have mastered 1-12? Or is it better to focus on other areas of weakness in Maths.

Curious because dd is fast and accurate with times tables up to 12 but she lacks confidence in fractions, decimals and percentages, word problems and I'm sure a few other areas I've yet to uncover, I would have thought it's better to help her with these at home but she says if she doesn't learn the 13, 14 and 15 times she'll lose her break. I know I need to speak to her teacher about this, maybe I've got it all wrong though - hence would really appreciate views. I thought 1-10 was enough now, never mind 1-15, I would have thought is was better to focus on areas of weakness rather than memorising too many number facts. Dd is in Year 6.

NoComet Wed 23-Oct-13 09:13:31

15 is easy because you know the beginning from learning the time and it has a nice pattern.

Can't see any reason for 13/14

TeenAndTween Wed 23-Oct-13 09:30:58

Can't see any reason for knowing 13-15 at all. I don't know all at instant recall, though likely to have a 'feeling' about some of them.

Occasionally helpful if you want to factorise big numbers, but not worth putting effort into knowing imo. Much better to focus on other areas of weakness.

The useful ones would be to know the squares, esp 13^2=169, as useful for Pythagoras 5, 12, 13 triangles later in secondary.

My DD1 is y10 and is not hampered by not knowing these. Though is definitely hampered by not being able to apply tables 1-12, (eg recently simplified 6/12 to be 1/4 ).

Better imo to be able to do long multiplication (at least grid method).

(Maths degree)

PastSellByDate Wed 23-Oct-13 10:14:47

Don't really know of anyone around here being asked to learn x13 - x15 in KS2.

However - you do know you can think of it as anything x 10 plus anything x 3 - so for example 8 x 13 = (8 x 10) + (8 x 3) = 80 + 24 = 104.

Perhaps the easier thing to do once numbers exceed x12 is to teach them 'long multiplication' (in old money) - I guess now termed short multiplication.

But basically ye olde vertical mutliplcation: a nice summary of two ways of doing it is here:

www.homeschoolmath.net/teaching/md/multiplication_algorithm.php

This is logically (and internationally) the next step with multiplication after learning tables from x0 - x12.

If you haven't come across it Math Drills - has some lovely worksheets you can print out (come with answers) - for extra practice. Link here: www.math-drills.com/ - you do have to explore a bit - but there's tons of great stuff there.

HTH

SparklyFucker Thu 24-Oct-13 12:27:11

As a side note, rather than 13 & 14, 16 is a useful one to know in terms of electronics and general engineering - lots of things are base 16 in science/techie fields.

juniper9 Thu 24-Oct-13 17:15:28

By the time you get to the teen numbers, I'd expect a child to use partitioning. For example, 13 x 8 = 10 x 8 + 3 x 8.

You could rote learn all the multiplication facts if you wished to, but I don't really see the point.

Thu 24-Oct-13 20:52:03

The curriculum (I'm in Wales, but I don't think it's any different) at KS2 only requires the children to develop their recall of the multiplication facts up to 10x10. We still do 11s because the children find them easy, but if they know all their facts, they can then work out 15s, 17s or any other.

Thu 24-Oct-13 21:13:29

I don't know anyone in our area of SW London who is learning them above 12x at primary.....

...and I utterly agree, Snowlike, it makes more sense to help her with the areas she lacks confidence in. I would have a chat with her teacher

Buggedoff Thu 24-Oct-13 22:37:03

No need to learn above 10 times tables IMO, because fluency in partitioning should help you above this.

Does anyone know why times tables are traditionally taught to 12's? Is it harking back to old fashioned weights and measures?

strruglingoldteach Fri 25-Oct-13 06:51:51

They only need up to 12 x 12. I think it is a waste of time learning by heart beyond that, although they should be able to calculate them mentally very quickly. Far better to focus on other areas of weakness- definitely discuss it with the teacher.

Fri 25-Oct-13 18:53:37

I believe it has something to do with the fact that there used to be 12d in a shilling.

missinglalaland Fri 25-Oct-13 19:22:59

PastsellbyDate thanks for the link to to Mathdrills. I had never heard of it before, but it could come in handy!

Iamnotminterested Fri 25-Oct-13 21:27:28

DD2 has learnt x 13 tables because she had passed all of her x and division up to 12 at school. But she is that kind of child. I don't know my 13 x tables...

CecilyP Fri 25-Oct-13 21:34:40

Does anyone know why times tables are traditionally taught to 12's? Is it harking back to old fashioned weights and measures?

Yes, not so much weights and measures, rather than when currency was shillings and pence.

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