Subtraction

[Kassee]

How do kids learn to subtract nowadays. Say take 600 - 426 = ?
When I was at school you added 10 to the top and one to the bottom (I still do today) but my granddaughter is having none of it. But cant remember how she was taught to do it. Just started senior school. Thanks.

[Jackdaw33]

Would that be using slide rules or logs?

[jourdain2]

I borrow 10 and carry 1 - very simple and it makes sense.

[bednobs]

ha! until i read this question, i hd no idea it was done in different ways! I was tught to borrow from the next column to the left and just ssumed tht was "the" way!

[fiction-factory]

Yes, that's the most common way but it gets a bit trickier for some when you have to borrow from a zero

[Jackdaw33]

That's what I found FF when trying to teach it the 'new' way.

[woofgang]

that’s easy...pass to next column, borrow one and pass back down

[Jackdaw33]

It's a bit like dividing fractions. I was taught to invert the numerator and denominator and multiply. I was a wizard at them at the age of 10 but I was about 14 before I understood the process.

[jno]

As far as I can see, Kassee just wants to be told what method her granddaughter uses. Not really seeking a disquisition on how much better the old methods were when we all had hundreds of fingers to count on...

[whiskeryron]

All this gobbledegook. In your example ''600 - 426'' I simply deduct mentally 600-500 then add 74 = 174.

[whiskeryron]

because it is easier to deal with whole numbers ( when you deduct the 426 call it 500 ) the difference between 426 & 500 is 74.

[Jackdaw33]

No need for that, jno, and your use of 'disquisition' is precious in the extreme. I have never used that word in all my life.

[jno]

That's a proud boast, Jackdaw.

But I was merely suggesting, politely, that the discussion was going off topic without answering the OP.

[weecalf]

the word subtraction is it an underwater stretcher

[fiction-factory]

It may be worth mum/dad asking the school if the child doesn't know. We have explored various ways here but we can't be certain how the granddaughter was taught. I know how it's taught in the schools I've worked in but I would not discourage any child from using another method if it works for them.

[Peter Pedant]

actually Murdo
there were a variety of ways

in the good old days of the British raj the boys and gurlz in India
would do the borrow 10-6 equals four
and then the pay back was below the calculation
so you then went ten minus two is eight- SUBTRACT the carry is seven
six minus four is two subtract the carry is one .....one-seven-four

how do I know ?

at age eight sister marie-christine went on holiday and sister Veronica took our class ( fundamental arithmetic but sister V was no fun at all ) and in around ten minutes destroyed like forever our ability to subtract.
Took the rest of term to get over that one
and us kidz ? made us very wary of 'new' teachers 'just coming in for this lesson'

sister veronica had been brought up in india
my mother also british rag said later - yeah we did it like that youre right

even in the fifties changing primary schools was chaos