[MMaschin]

Unfortunately for me, I did immediately see a pattern, and I came up with 128. I thought it was a little advanced for first graders.
16-6 =10
68-88=-20

So logically the pattern would indicate the difference between the next two numbers should be +30. So ergo, 128.

128-98=30

[dfwgator]

Unfortunately for me, I did immediately see a pattern, and I came up with 128.

I did the same thing.

[eyedigress]

or 68 (98-68)