any teachers here?

[cutekids]

My ds1 (YR 4) has brought a sheet of h/w home which we are not sure about.
"near doubles"
Eg: 36 + 37= DOUBLE 36,PLUS 1
= 72 + 1
= 73
Now, although that makes sense to us, we have another one which is
80 + 90
Do we say,DOUBLE 80,PLUS 10
= 160 + 10
= 170 ?????
OR: do we say, 80 + 90 = 170
= DOUBLE 85 ??????!!!!
anyone know????[embarrassed]

i'd say

DOUBLE 80,PLUS 10

double 80 plus 10
=160 + 10
= 170

if it's double 85 it's not a 'near' double.

double 80 plus 10.

that is from what I rmember from one of those support your child maths evenings.

THANKYOU,THANKYOU,THANKYOU!!!
So,360+260
WOULD BE DOUBLE 260,PLUS 100
= 520+100
= 620???

Or 360 + 360 - 100 but I expect they just want you to stick to addition for the moment. As you were

The thing about mental methods should be that you do in your head what works best for you. The teacher should celebrate each individual mental method. There are no right answers.

As a teacher,would you go by what i suggested bearing in mind he's only just started doing these. (year 4)???

jeez i'm glad I don't have to teach year 4 maths!

oh i see, so there are no hard and fast rules then?

there are always right answers
there are no right methods

I teache year 5 maths,,,,

They are basically using there knowledge of doubling to help them to calculate near doubles.....

double the 80 then add the 10 on

I'm so glad I don't either,Lucycat!!!

now year 13 geography that's not a problem but Maths.....

you need the site that i keep posting links to...hold on

Would certainly do double 80 plus 10 myself! Different methods do seem logical to different children. Getting the right answer is what is important. In my experience they can find it hard to express the calculation they are actually doing in their head and then of course if they are feeling under pressure there is nothing much going on in the head at all! Carry on as you are I'd say!

bumped y maths thread for you

thanks everyone.really appreciate your input. my ds1 has a great knack of doing all his sums in his head (don't know where he gets that talent from!) but cannot express himself on paper! In other words, he can tell us all the answers but can't explain how he got there!!!

Wouldn't worry in that case!