In not being able to do my 10 year olds math homework!

[Livesforbedtime]

I don't understand this.. She has to work out 23 x 22..

Now I'm not the sharpest pencil in the box, but I have a degree and a responsible job... So WHY when I worked it out as:

20 x 20 = 400
2 x 3 = 6

Answer = 406

But it's not is it? It's 506.. But I don't understand why

My poor 10 year old DD is bewildered.. And I cannot understand why I'm wrong yet I know I am!

I suspect it have a mind block... Yes that's it.. I'm not truly stupid ok I might be..

It doesn't make sense!

[anothernumberone]

Kim is their research showing which method is more successful for children's understanding and achieves more successful outcomes? I personally am admittedly biased having learned one way myself but that second method you posted is v complicated.

[anothernumberone]

Is there even

[BlueberryWoods]

What's the bus stop method? Not heard of it.

[PolkadotsAndMoonbeams]

I usually use 'normal' long multiplication, but would only write two rather than four answers to sum (if two two digit numbers).

However, for 62 X 75 without a calculator/piece of paper I'd be more likely to do 62 X 100, then divide by four and multiply by 3.

[OldMacEIEIO]

Lives For Bedtime
I have some good news and some bad news.

The good news is that the answer to your sum is 506. It always was (even when jesus went to school), and it always will be (even when your delightful daughter becomes a successful maths teacher)

the bad news is that you are thick as a plank

[Oblomov]

Never knew it was so complicated.

[Impatientismymiddlename]

What's the bus stop method? Not heard of it.

its the column method, but some schools now call it the bus stop method as it helps children to visualise the carried numbers as 'waiting for the next bus to come along and get on'.

[anothernumberone]

Kim you are actually adding in 2 new steps with the grid method you demonstrated compared to the traditional method.

To me that looks like a greater degree of complexity. The algorithm for traditional multiplication involves breaking only the second number down into its units and 10s and then multiplying the units by the first number and then the 10s by the first number and then adding. The grid system involves both numbers being broken down to units and 10s and 4 calculations being carried out before adding. This is increased further when you introduce hundreds. Personally although as I said I am biased I would see more scope for error with the second version given the additional calculations but better scope for understanding. I am not sure which is better for mental arithmetic though a right answer or a deeper understanding.

Does the research support the grid or traditional method or is it just a question of whichever the teacher is more comfortable with?

[PolkadotsAndMoonbeams]

I think I must be strange, I wouldn't do 8X36 as 8X30 and 8X6 mentally, although if I were doing written long multiplication that's exactly what I'd be doing

In my head I'd do 10X36=360, and then take away 72 to give 288.

[anothernumberone]

Kim I could not agree more. Multiplication is important so students can approximate results but accuracy is over rated that is what a calculator is for IMO. I cannot add, multiply or subtract but I got a first in maths every year for 4 years in an engineering degree and I manage to teach applied maths without many mental arithmetic skills.

[Impatientismymiddlename]

But who would do 1215 x 321 nowadays without a calculator?

My 9 year old would and so would lots of other 9 year olds.
My 9 year old would try and use the traditional column method though as he finds it much easier and quicker. He hates gridding with a passion.

[NoodleOodle]

I didn't understand that grid thing by the explanations on here, having never seen or hear of it before, but the youtube video posted makes it make sense. I learnt the bus stop way and that will always be easiest to me, but I can see how they both work.

From the youtube link, the Japanese method is in the sidebar - that looks way cool!

[notso]

My brain can't/won't do maths. I panic when I am faced with a mathematical problem.
It took me three attempts to scrape a C grade in my GCSE.
I have tried and tried to learn times tables with songs, reading them over and over again even recently with an app and I just can't retain them.
I had to pretend I needed a wee and went and cried in the bathroom when DS1 9 asked for help with his homework the other night.
It was multiplying fractions. DH helped him and showed me how to do it. I understood then but just tried to do one now and I can't.

[IceBeing]

[NumTumDeDum]

I don't know any of these methods! I struggled with maths throughout school until I left secondary school in year 3 (9) and started a new school in year 4 (10). None of my records followed so they put me in a higher class by accident. I understood nothing the teacher said, went to see her at lunch in floods of tears, and she tutored me a couple of lunchtimes a week throughout year 10. I got a b in the end- but all using a calculator because that was what was required by the examining board. I wish she'd been my teacher throughout, I'd have learned so much more.

[Impatientismymiddlename]

But in the real world, people do not need to do that calculation.

Unless you count being able to help your 9/10 year old with their homework and come up with the correct answer rather than the wrong answer as 'in the real world'. I'm glad that I can manage most basic forms of mathematical concepts as I have been able to assist my children. I would feel quite pathetic if my 9 year old came to me for help and I was unable to do so due to not understanding basic long multiplication and other such concepts. I have actually considered doing an online maths refresher course as my son will soon start to learn algebra and it isn't something that I was ever any good at.