The Singing Hedgehog Guide
to:
Addition
The most common mistakes
here are to do with carries.
Here is a list of dos and dont's that should help:
- always write the carry - you will forget it!
- place it below the answer line - easy to ignore it anywhere else
- put it in the correct column - it must have a real value
- don't cross it out as you use it - easy to cross out but not add on
Here is a set of wrong answers showing each of the above:

And the right answer!
Now you need to practise: