Subject-verb agreement means that your verb must be conjugated, or changed, to fit (or agree) with the subject. Subjects can be singular or plural. Think of singular and plural as mathematical ...

In this case, be careful about whether you are taking in the singular or plural meaning and make sure to change the verb. Other examples include: economics, sheep, politics, headquarters ...

The subject-verb agreement is tricky in a sentence or dependent ... on the sidewalk," the real subject is "penny," so the word there is treated as singular. Study these examples.