Oh thats an easy one. There is also 'bc' but that would be for really hard core math, and then there is "let".. but dont worry with those.. you can just use awk.
Code:
-bash-3.2$ cat test.txt
one 1
two 2
three 3
four 4
five 5
six 6
seven 7
eight 8
nine 9
ten 10
-bash-3.2$ awk '{count += $2;} END { print count; }' test.txt
55
