It might be possible to work this in your head. Your 98 is 100 minus 2. This means 98 plus 98 is 100 plus 100 minus 2 minus 2. That's 200 minus 4 which gives 196 as the answer.
7,840
196
34 + 98 + 98 + 87 + 32 = 349
158
99 + 98 + 97 = 294