Maths!

[V8LM]

TheInternet said:

36^0.5

Ooops

[turbobloke]

Simpo Two said:

Speaking as an idiot, I see it as essentially a right-angled triangle. One side is 20m, you just need another side - here the distance between croc and bank. Is the croc on the opposite side of the river? Looks like there's a bit more bank there to cross... is the diagram to scale? How far is the lunch from the bank?

Hardly speaking in that way!

The question was a reasonable set-up as a calculus item and very well crafted.

All it needed, with icing already on the cake, was a cherry on top. Students will have known from the question wording and their answers to the first parts that they had found a minimum but the item writer might have asked about the nature of d2T/dx2 (+) in keeping with this.

[Hoofy]

Moonhawk said:

Fonz said:

Moonhawk said:

I quite like the Japanese way of doing multiplication - very easy and visual method.

Could someone please explain this to me as I'm just not getting it. :

You represent the numbers by drawing diagonal lines (so 22 is represented by two sets of 2 diagonal lines). Similarly for 13 crossing the diagonal lines so you end up with a diamond shape.

You then divide the diamond shape into columns and add up all of the intersections in each column.

https://www.youtube.com/watch?v=_AJvshZmYPs

Edited by Moonhawk on Wednesday 30th September 16:13

If you need all that space to draw that on paper, you might as well do it the normal way!

[Flibble]

Hoofy said:

If you need all that space to draw that on paper, you might as well do it the normal way!

It's also a right faff when the numbers get big. The examples always use something like 22x13 which is nice and neat, but try using it for 8897x7876 and you'll need a full sheet just to draw it out!

[Moonhawk]

Hoofy said:

Moonhawk said:

Fonz said:

Moonhawk said:

I quite like the Japanese way of doing multiplication - very easy and visual method.

Could someone please explain this to me as I'm just not getting it. :

You represent the numbers by drawing diagonal lines (so 22 is represented by two sets of 2 diagonal lines). Similarly for 13 crossing the diagonal lines so you end up with a diamond shape.

You then divide the diamond shape into columns and add up all of the intersections in each column.

https://www.youtube.com/watch?v=_AJvshZmYPs

Edited by Moonhawk on Wednesday 30th September 16:13

If you need all that space to draw that on paper, you might as well do it the normal way!

There is no "normal way" - simply the way you happen to have been taught.

[RobM77]

Moonhawk said:

Hoofy said:

Moonhawk said:

Fonz said:

Moonhawk said:

I quite like the Japanese way of doing multiplication - very easy and visual method.

Could someone please explain this to me as I'm just not getting it. :

You represent the numbers by drawing diagonal lines (so 22 is represented by two sets of 2 diagonal lines). Similarly for 13 crossing the diagonal lines so you end up with a diamond shape.

You then divide the diamond shape into columns and add up all of the intersections in each column.

https://www.youtube.com/watch?v=_AJvshZmYPs

Edited by Moonhawk on Wednesday 30th September 16:13

If you need all that space to draw that on paper, you might as well do it the normal way!

There is no "normal way" - simply the way you happen to have been taught.

Surely he just mean the 'normal' way for the UK, i.e. the way most children are taught at school, which isn't the above method.

[Einion Yrth]

RobM77 said:

Moonhawk said:

Hoofy said:

Moonhawk said:

Fonz said:

Moonhawk said:

I quite like the Japanese way of doing multiplication - very easy and visual method.

Could someone please explain this to me as I'm just not getting it. :

You represent the numbers by drawing diagonal lines (so 22 is represented by two sets of 2 diagonal lines). Similarly for 13 crossing the diagonal lines so you end up with a diamond shape.

You then divide the diamond shape into columns and add up all of the intersections in each column.

https://www.youtube.com/watch?v=_AJvshZmYPs

Edited by Moonhawk on Wednesday 30th September 16:13

If you need all that space to draw that on paper, you might as well do it the normal way!

There is no "normal way" - simply the way you happen to have been taught.

Surely he just mean the 'normal' way for the UK, i.e. the way most children are taught at school, which isn't the above method.

And doesn't need an A2 sized piece of paper to multiply 2 four digit numbers.

[Moonhawk]

Einion Yrth said:

And doesn't need an A2 sized piece of paper to multiply 2 four digit numbers.

Well yes - nobody is suggesting the visual method is applicable in all circumstances, it does become unwieldy pretty quickly, however, it could certainly help children who may be struggling with the more traditional ways of tackling multiplication.

Different kids learn in different ways - I think we should be open to new ways of learning/teaching. Japan certainly doesn't seem to suffer from using this method - they rank 7th in the world for secondary school maths attainment (the UK for comparison sits around 28th).

http://www.oecd.org/unitedkingdom/PISA-2012-result...

[RobM77]

It's a nice method for sure, but it's pretty standalone - i.e. it doesn't develop skills and understanding that can be used in other forms of arithmetic or in more complex calculations. It's also difficult to do in your head. If you look earlier in the thread I talk about multiplying decimals and long numbers etc, which is a good example of aggregating simple skills to do more complex things.