Hi,

I am new to this forum and really really hoping you can help me! I am only university age (in the UK) but with an A Level in Maths, I spend some spare time tutoring friends' children. I am currently tutoring a 16 year old girl studying for her GCSEs. Obviously it is important that her knowledge of the curriculum is near perfect, but she struggles with her basic number knowledge and mental maths - this therefore affects her question answering time.

I provide her with simple worksheets and time her whilst she completes them.. but I have recently provided a sheet that has me STUMPED! Any suggestions to the following problem would be greatly appreciated...

Basically the problem is "long subtraction", which doesn't really exist, it's simply subtraction, e.g:

10

- 8

= 2

For a very young child to do this, you could suggest "taking" the 1 from the first column and making the 0 a 10, then 10-2 is 8. This is obviously a very simple question to prove my point.. please try the following, imagining you are a young child who has just learnt this method...

34

- 38

= ?

We know that the answer is -4 but how do you show this using the subtraction method. If i take "1" from the "3" in the top left column then the 4 becomes 14, 14-8=6.. then 2-3=-1.. the answer would show as -16???? VERY CONFUSED! Is this even possible?

Help!!! Thank you for reading