SPILL ERROR CAUSING MORE WORK NOT REDUCING IT _ MAKE IT OPTIONAL!

[BonsaiTree]

OK, so I admit I am not a power user and frankly have no real use for the SPILL thing. All it does is cause me frustration and anger at having doing more where before it wasn't required. I want to use this formula to look at a row of unique numbers and see if one from another table is there. The formula I am using used to work no problem. But now I get Spill error and I have no way to figure out how to correct it. The instructions/solutions I've seen don't match what is showing up on my worksheet. 

Here's the simple forumula:

=IF(A12=(A3:A8),"Y","N") 

A3-A5 is the range I want it to look at and consists of unique numbers, no repeats.

A12 is the number I want to match to see if any of the cells A3:A8 contains it.

When I highlight the formula there is a dotted blue line around the formula cell and the 6 cells below. That I assume is the spill area. But how do I build this table so that it looks up more numbers in the column to match?  So far everything anyone has suggested that I've found doesn't get rid of the #Spill error. What exactly is it trying to do and why would you screw up such a basic spread sheet functions like this for something many of us will never use?

[#2 · Accepted solution]

@BonsaiTree 

In my opinion you screwed up your formula.

The part A12=... requires a single cell and not an array of cells. The correct form would have been:

=IF(A$12=A3,"Y","N")

The reason why it still worked in old Excel is "implicit intersection".

In new Excel you have to explicit use the implicit intersection operator.

=@IF(A12=(A3:A8),"Y","N")

Or just let the formula spill.

[#3]

@Detlef Lewin thank you so much for this.  Using the @ worked in my SumIf and resolved the error I encountered.  For those of us that didn't understand the change in Excel and what it was doing, your brief explanation below helps to clarify and will help with other formulas.