Calculating the Year to date of a portfolio

Hey there investors! I'm keeping track of my daily performence within an Exceldocument as my broker doesn't offer many features like total return in percentages and fun graphs to show your growth. I've been calculating my growth by doing the (new-old)/old example: (120-100)/100 =20% growth. But after keeping track of my portfolio I see the percentages feel very skewed. Here is an example to show what I mean:

Begin balance _______end balance________money added___________daily %_________cummalative%
2000_____________________ 2200__________________ 0_____________________10%______________110%
2200_____________________2300__________________ 0_____________________4.5%______________114.5%
2300 _____________________2900__________________ 0 _____________________26%_____________140%
2900______________________2400_________________400____________________-17%_____________113%

Let me explain what is happening above here. I start with 2000 which is my breakeven point. On the last day I started with 2900 and added 400 during that day. At the end of the day I finish with 2400. Exactly my breakeven point. Because i started with 2000 and added 400. Yet I still have a 113% performence. What am I doing wrong?

Thanks in advance!