Do any of your students get in a mess with “double borrowing”? There’s a very simple solution which builds on their existing knowledge of subtraction with borrowing….
Easy subtraction – one “layer” of borrowing
- Much harder subtraction – the borrowing cascades from left to right and is very likely to go wrong.
There is a very simple solution to this, encourage the student to look at the number differently. Borrow ONCE from the “200” on the top, which becomes 199.
Borrow ONCE from the “200” in the top number – now this sum is ready to do, and there’s far less that can go wrong.
Try it on a student near you, and use the reply box to tell readers what happened next!
Bellropespider 
When I tried this on a 12 year old low attainer I got a look of deep mistrust, as if it was impossible for maths to be that easy. Now they use it all the time.
Thanks Ben, your feedback is much appreciated. What else do they struggle with? (One topic at a time please!!)
Rosalind