Clear data but keep cell values

A2 Contains value1 say 10 for example B2 contains Value2 also 10 C2=A2+B2

A2
10

B2
10

C2
20

I need to clear the values in A2 and B2 but keep the answer in C2 and transfer it to C3
Next day new values are entered in A2 & B2 answer is in C2
C4=C2+C3

This is a simple example of a much larger project the problem I am having is when you clear the values in A2 and B2 the answer obviously has to be zero.

Anyone know of a way to do this maybe with variables?

Thanks
Charles

Since you haven't had any other responses, you might want to try this equation in C3 :
=IF(AND(A2<>0,B2<>0),C2,C3)

(C2 would have =A2+B2, as I believe you already have.)

Now the equation in C3 has a circular reference, so an error message will come up referring to this circular reference. You will need to ignore this each time, or set the iteration option and number of iterations to 1 on the Tools|Options menu (tab - Calculation).

I have tried this out and it seems to work, but you (or others) or your spreadsheet (something else might be thrown off by using iterations) may have objections to using iterations.