I am creating a pipeline that has new data entered each week. I want the
weekly figure to automatically add on to the monthly figure.
Eg.
A B C
1 Weekly Monthly YTD
2 $100 $500 $600

The monthly will get cleared to $0 at the beginning of each month but I want
the YTD to continue increasing. So when I enter a figure into A2, I want it
to add on to C2 as well.
Help please - thanks