=IF(AND($K$4>=1,$K$4<=4),"+2",IF(AND($K$4>=5,$K$4<=8),"+3",IF(AND($K$4>=9,$K$4<=12),"+4",IF(AND($K$4>=13,$K$4<=16),"+5",IF(AND($K$4>=17,$K$4<=20),"+6","")))))

This is without quotations, however it now responds as a blank cell due to my "" for false, for some reason it is not seeing the numbers in the CELL, the CELL that is reference has a long IF AND function in it as well which is to calculate base on another cells input, unsure if this is a problem which I assume not.

As for your suggestion of the lookup function, yours returns N/A and I am not familiar enough in it to trouble shoot that. However it looks as though in the LOOKUP you are looking at a list of cells and it searches those cells for your query, well I need it checking the one cell and anything equal to and between 1-5 is to have 2 which as said would work with quotations around the numbers but won't work without quotations.