Circular dependency workaround on google sheets

[svcellular]

I need to make a google sheets cell that collectively adds itself to the value of another?

Like if B1 currently says 20, and I put a 5 in A1, and enter to write the cell, make B1 25. Then tomorrow, I enter a 6 that makes B1 31.

 

[sijpie]

I haven't worked with Google Sheets that much. Does it have events you can use in macros? In Excel you could use a help cell which the change event for cellA1 (or whatever) stores the current value of B1, then sets the value of B1 to the help cell plus the sum of other cells involved.