Answer :

2.3  + 6.82 : 3.74 + 1.09 = 3.39 + 1.8 = 5.19 
BIDMAS
6.82/3.74 = 1.82352941176
2.3 + 1.09 = 3.39
1.82352941176 + 3.39 = 5.21352941176

Unless you didn't include brackets, which would result in a different answer