Summing up horizontally

I need to sum up the Ord Unit & Sales Amt horizontally from Jan - May/17.
Currently, I simply add up each cell as shown in the picture under total column. Is there any formula function the same without adding up each cell one by one?

Try placing the following formula in cell L3 and drag-copying it down and right as needed:

=SUMIF($B$2:$K$2,L$2,$B3:$K3)

Works perfectly. Many thanks for your help.