# Talk

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

(147 Posts)
Livesforbedtime Wed 05-Mar-14 18:51:11

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

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!

welshnat Wed 05-Mar-14 18:52:52

It's 23 x 20 + 23 x 2 = 506

welshnat Wed 05-Mar-14 18:53:22

It is an easy mistake to make though. I had to think twice

DarlingGrace Wed 05-Mar-14 18:53:22

Because you dont work it out old school LMAO

23 X
22
460
_ 46_
506

Wed 05-Mar-14 18:53:39

It's 23 lots of 22, though, so your way makes no sense at all...

Is that how the school have asked them to do it??

Wed 05-Mar-14 18:53:48

Wouldn't you do 20x22= 440
3x22=66?

TheWomanWithTheMysteriousLump Wed 05-Mar-14 18:54:26

You have to multiply the two 20s by the 2 and the 3 as well.
20*20
+2*20
+3*20
+2*3
=506

Wed 05-Mar-14 18:54:28

startwig1982 Wed 05-Mar-14 18:55:00

It's because you need to do:
20 x 20
20 x 2
3 x 20
2 x 3
You must multiply all the bits together.
Most children learn by grid method where you split the numbers into tens and units, therefore having 4 sums that you add up at the end.

LIZS Wed 05-Mar-14 18:55:20

20x20= 400
20x2=40
3x22=66
total 506

Livesforbedtime Wed 05-Mar-14 18:57:22

Oh god so I am stupid?!

It's just made sense now. Honestly I was so adamant I was right! My poor DD is now more confused than when she started!

Must learn to just leave well alone!

Wed 05-Mar-14 19:01:14

Think of it more as

20 x 22 and 3 x 22

which would be

440 and 66 = 506

Using your method, you also have to do 20x2 and 3x20. Does that make sense?

Livesforbedtime Wed 05-Mar-14 19:01:54

Ohhh that makes much more sense!!

Logg1e Wed 05-Mar-14 19:04:25

If you can't do 23 lots of 22, can you do...
2 lots of 22?
4 lots of 22?
10 lots of 22?
20 lots of 22?
And so on.
Can you use these facts to get to 23 lots of 22?

Wed 05-Mar-14 19:06:19

I can't do my twins year 4 maths. My DD's year 7 maths is beyond me. I learnt Smile maths at my comp and it has a lot to answer for!!!

Ubik1 Wed 05-Mar-14 19:08:15

My DD aged 9 has now surpassed my levels of arithmetic , only DP with his superior Scottish education can help her - although he told me the other day that he has 'forgotten all my trigonometry'

I did statistics as part if my degree and it all made sense to me but adding, subtractionabd long division? Nah.

Laurasmile Wed 05-Mar-14 19:14:39

Unsure of what multiplication method she'll have learnt at school - but the grid method for multiplication gets taught at secondary and helps avoid making that mistake - handy youtube tutorial

Ubik1 Wed 05-Mar-14 19:16:20

Oh we did Smile maths as well - basically you left school being able to draw nice pictures but no idea how to actually calculate anything. Can draw a great pie chart though. Never learnt my times tables either.

Livesforbedtime Wed 05-Mar-14 19:18:56

Oh see now this is more like it.. Feel much better now I too can do an almost bar chart.. It's a work of art really...

Livesforbedtime Wed 05-Mar-14 19:19:13

awesome

Ubik1 Wed 05-Mar-14 19:28:57

It was really important to choose nice complementary colours and colour in carefully. New felt tips made it extra special

soverylucky Wed 05-Mar-14 19:30:06

Message withdrawn at poster's request.

Wed 05-Mar-14 20:34:34

I did a Smile Maths, went on to do A level Maths and a Physics degree!

Wed 05-Mar-14 20:37:45

YABU to call it math though.

Livesforbedtime Wed 05-Mar-14 21:06:37

MathS honestly you people that deliberately correct people constantly really bloody irritate me.

I didn't ask for a grammer/spell check and I really dislike the snidey 'ooh look what I found.. A mistake!

Do you guys have any idea how absolutely childlike and pedantic you come across to average normal people?

Join the discussion

Registering is free, easy, and means you can join in the discussion, get discounts, win prizes and lots more.

Register now