Grady received $8,680 of Social Security benefits this year. Grady also reported salary and interest income this year. What amount of the benefits must Grady include in his gross income under the following five independent situations?

1. Grady files single and reports a salary of $13,300 and an interest income of $370.

2. Grady files single and reports a salary of $23,320 and interest income of $720.

3. Grady files married joint and reports a salary of $77,400 and interest income of $620.