Are you perhaps clicking on a cell containing the 2 when creating the formula?
With the keystrokes and mouse actions described below the table, I get this result:
Click A1. Type 3000 tab
(in B1) Type 2 tab
(in C1)Press =,
(in formula editor) click A1, type spacexspace, click B1 (x is a lower case letter x, not the multiplication symbol)
Note the + sign. Numbers inserts this default addition operator if you have entered two cell addresses without a separator ( , or ; depending on region) or a different operator ( eg. -, *, / ) between them.