In order to add these numbers, first let's write all of them with the same number of decimal places:
17.34 = 17.340
8.03 = 8.030
0.009 = 0.009.
Then, let's add all algarisms that are in the same position in each number:
0 + 0 + 9 = 9
4 + 3 + 0 = 7
3 + 0 + 0 = 3
7 + 8 + 0 = 15 (5 plus 1 to next algarism)
1 + 0 + 0 (+ 1) = 2
So the final result is 25.379.
