Excel | How to Add 2 or more SUM's together

[struic]

Hi all, 

Been facing this weird issue where I don't know how to add SUM-1, SUM-2 and SUM-3 together. I want to calculate the total of these 3 SUM's but just doing: =CELL+CELL+CELL doesn't work. 

It gets me to 0

No error is shown. 

Seems like a very very simple equation to make so if anyone knows how to do this, please let me know. 

Kind regards, 

Marc

[#2]

@struic 

Could you provide more detailed and specific information? Preferably with one or more screenshots.

[#3]

Fixed! Thanks