This animation (which you can find on “Maths Tools – Adding 3-digit numbers”) might help you to understand how regrouping works.
ADDING 3-digit numbers with regrouping
This works for 2-digit numbers, 4-digit numbers and so on…
Practise using this and challenging yourself using paper too, to see if you can do as well as the computer and get them correct.
😎
Now you can also have a go at subtracting with regrouping. Use this animation to see how it works.
SUBTRACTING 2-digit numbers with regrouping
This should feel much simpler for you now.
🙂