Maths challenge - any ideas?

[Cantdosums]

Please see image - I'm totally stuck!

Trying to improve my maths capabilities but think this is too advanced for me - I don't have gcse maths - thinking about going back to college as a mature student (has anyone done this?) but anyway, can anyone do this one? I just don't know where to start on this one ?

It's 25. Add up each column to get the numbers in the bottom row.

Add up the first 3 numbers in each column

add the columns gong down

Doh!

Thankyou

@Cantdosums if it makes you feel better I didn't get it either and I was really good at maths at school! Don't be discouraged!

I don't see it as a lack of maths knowledge. Stuff like this is about being able to spot patterns/sequences so don't let it knock your confidence.