Arithmetical embarrassment - please help

[Aparecium]

I've forgotten how to do column subtraction! How do I borrow from a column with a zero?

Yes

Take 1 from 20, thus leaving 19

Surely instead of changing the 2 to a 1, you change the 4 to a 3 in the second column from the right?

You can’t borrow from 0. So go next door and consider it that you’re borrowing from 20. 20 less 1 becomes 19 so strike through the 20 and write 19 in its place. Continue to solve as normal then.

This

So, borrow 1 from the 2 (leaving 1) to give 14-8=6
Borrow 1 from 20 (leaving 19) to give 11-4=7
Then 19-1=18
2024 - 148 = 1876

Huh? No that's not right..

I learned it as borrowing and repaying... so you can't take 8 from 4 so you borrow 1 from the tens column, then you need to repay it. But from my experience with my kids this is not the easy they learn it.
Here's my calculations, not sure if helps. But it's how I do it. Ooopss!! Can't subtract... Thursday night wine - should be 1876

You are absolutely correct, but will have confused some posters because this is an alternative way of doing column subtraction which is no longer taught. When I did my PGCE 20 years ago, I was told that I must have had quite an old teacher (yes!) and have been one of the last pupils to have been taught this method! I had to re-learn column subtraction to 'borrow' (regroup) from the next column to the left on the top row.

The current method borrows from the top row and decreases the number by one, but I was taught to 'borrow' from the bottom row and increase the number by one. It made the process easier, but was something we learnt by rote, rather than having any deep understanding of how it worked.

Considering it as borrowing from 20 makes sense. Twenty 100s, rather than zero 100s and two 1000s. And then the borrowed 100 makes the one 10 become eleven 10s.

Thanks!

Next: long division.

Borrow across the 0 - make it a 10 then take 1 from that to have 11 in tens column, 9 in hundreds.

Look I think the only thing I got right on my O level Mathematics was my name...!

...you've made my brain hurt.

I'm good at mental arithmetic but write it down and I struggle with it like a cat being given a tablet.

I am not good with numbers, either written down or in my head...

This has genuinely made my brain hurt. How I passed GCSE maths is a mystery!

No. Under the old method (which I learned in the 1960s), you pay back into the bottom row.

So in the units column, you can't take 8 from 4 so you borrow one from the tens column, making the 4 into a 14. 14 - 8 = 6. Then you pay back that one into the bottom row of the tens column, making the 4 into a 5.

Then move left and carry on in the same way.

I'll try and attack a photo but am not confident it will work!

“Ten to the top and one to the bottom” was what I was taught in school.