Substitute text with a numeric value

[Frasier013]

I have created an archery score card for myself as per attached screen shot. In archery it's also possible to score an X (right in the middle) which has a value of 10. Is it possible to calculate is possible for me to indicate on my score sheet that I have an X, but my totals at the end would calculate it as a 10?
Ii've also included the Excel file too.
Thanks in advance.

Score card.xlsx
Screen Shot 2013-06-30 at 22.24.50.png

[Jakobshavn]

See the attached

[Frasier013]

Thank you! I knew it would be something relatively simple

[Ace_XL]

Another way..

=SUMPRODUCT(SUBSTITUTE(A1:A20,"X",10)*1)