Good morning.
I’m not too great with conditional formatting, still in practice.
Is what I’m looking for possible?
I’ve added a spreadsheet, but will also ask here.
Hopefully the spreadsheet makes what I’m asking a little easier to understand, because I’m now starting to confuse myself 
plshelp.ods (13.1 KB)
Is there a way to do:
IF SUM_of_CELLS (paid) is EQUAL to TICKET(MINUS/NO DECIMAL NUMBER)
I don’t know what you want done when the total is zero so I set cell style to Default, delete the first rule if you don’t want it. I suppose there are several ways to do this but I used INT function for both cell and Total, ROUND might be a better choice if you just wanted it within 1 pound.
plshelp94981EA.ods (14.8 KB)
I know what I’m asking for can’t be easy, so I’ll try to make a bit more sense. 
There is a ticket cell, which we manually enter a figure. (A2)
There is a sum cell (A3+4+5) which gives paid (A6), I’m trying to get it so that the figure(when summed) equals (A2) WITHOUT the decimal number.
So, A6 is A2 MINUS the decimal number.
TRUNC doesn’t seem to work, either so it’s to 0 or 1
Paid is formatted to show two decimal places, so of course it does so. Try formatting with no decimal places.
I figured out my own problem.
So I have an initial figure (Figure A), then a figure which is rounded down to 0. (Figure A Rounded 2 places)
I then used a sum formula to get a number and conditional formatting to say if it’s correct or not.
plshelp-sorted.ods (12.1 KB)