Power Query if not a number then x else y

[MartinL]

I'm trying to create a formula in Power Query which sums 3 elements
If the answer is not a number then enter M0 otherwise sum the 3 elements

Column12	Column15	Column16	Column87
Widget1	Red	Apples	M0
2	3	4	9

I thought the code would be something like

if Number.IsNaN([Column12]+[Column15]+[Column16]) then "M0" else [Column12]+[Column15]+[Column16])

But that does not seem to work I just get Error for the first line
Column89 is set formatted as ABC123

 

[RoryA]

You could use:

try [Column12]+[Column15]+[Column16] otherwise "M0"

or you could just do the addition and then use a Replace Errors step on the column.

 

[MartinL]

You could use:

try [Column12]+[Column15]+[Column16] otherwise "M0"

or you could just do the addition and then use a Replace Errors step on the column.

OK try was a new one on me.
That worked a treat