Using your example: -
1/1/20 to 31/12/20 = 12 whole months
I assume your monthly income is 500+800+600+450

Ignore " " marks in the following: -

1. In another cell write "Income 1/1/20 to 31/12/20 =" and right-hand justify it.

2. In the cell to the right of that enter "=SUM(D25)" and press Enter.
I cannot stop the forum converting what I am typing into a smiley so imagine the smiley replaced by ": D" together but with no space.


Hope I have interpreted your question correctly.