sheets conditional formatting to check individual row cells values against each other

Question

I need conditional formatting in google sheets to check if the sum of two cells is equal to a third cell and highlight the 3 cells if not. I would like to set this up with one conditional formatting rule.

X	Y	Z
2	2	4.123
2.5	2.5	5.0
2	2	4.0
2	2	4.1

e.g. in this example, all three cells in rows 1, 4 should be highlighted.

Ideally with one custom formula?

Answer 1

Assuming the values are in the range A2:C, use this conditional formatting custom formula rule for the range A2:C:

=$A2 + $B2 <> $C2