Prefix in cell

[labprof]

I have an excel spreadsheet that we are using for serialization of test specimens.
It has 18 columns with titles 1 - 18 across the top and 20 rows numbered 1 -20.
In each cell my lab techs will enter a unique serial number.
I need a prefix "AC" to appear in each cell with the number however I'd like it if the tech did not have to type this in.
Is there a way to program excel so that when they type in a number it automatically appends a prefix to it.

Example:

current 1 2 3 4

1 1245 1246 1247 1248


desired 1 2 3 4

1 AC1245 AC1246 1247 1248

Is there a way to write some code to have each cell appear with the prefix example of desired?

Any help would be greatly appreciated.

Labprof

 

[xlhelp]

Assuming number will never be negative;

Highlight you range;

Go to Format, Cells, Number Tab, click Custom and in the Type box enter "AC"0;0;

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