Homework help please. 700 - 596. How do you show the workings?

[ptangyangkipperbang]

DS1 knows the answer but his teacher wants to see his 'workings'. I don't want to confuse him by showing him the way I was taught.
He is adamant that when you 'borrow' from the next column nothing ever changes on the bottom line, just the top one. However, if that is the case how can he do the sum. I hope you understand what I mean!

His method seems to work until there is a zero on the top line.

Help. He's about to rip his homework up.

Hold on, I'll ask DD, she's in year 7 now, but she might remember.

Put 700 on the top line and 596 one the bottom. You do borrow from each column. from tens first and then hundreds. If you cannot borrow from the tens you go to the hundreds as in this case. You then have 10 in the tens column and you borrow from there so you are left with 9 in the tens and 10 in the units.

10 - 6 = 4
9 - 9 = 0
6 - 6 = 1

total = 104

Hope that helps.

On top row:

Cross out the 7 and replace with a 6.
Put a little 1 before the first 0 (you've borrowed to make it 10).
Cross out that 10 and replace with a 9.
Put a little 1 before the second 0 (you've borrowed to make that 10 now)

Now do the subtraction:

6 from 10 = 4
9 from 9 = 0
5 from 6 = 1

i.e. answer is 104.

heres what i would write hope it makes sense!

700

• 596 --

769 0 10

• 596

____ 4

76 9 0 10

• 596

____ 04

76 9 0 10

• 596

____ 204

104 sorry typo!

I type too slowly

Cross out the 7 and put a 6 and a 1 next to the 0 on the right of it then cross out the 10 and put a nine and then put a 1 next to the 0 on the far right so you have

6 9 10

• 5 9 6

___ 1 0 4

Hope that makes sense.

She did it the regular way! Borrow 100 from 700, then 10 from 100 and took 10 away from 6. Does that make sense! So hard to show on here! So, the sum looks like this:
69 (10)
59 6
10 4

Does he perhaps have to do counting up, rather than taking away?

from a much happier DS

Thankyou!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!

'Borrowing' isn't taught like it used to be. I would have thought he could set it out like this:

700

• 500 = 200
• 90 = 110

-6 = 104