This is a great refresher for students, or practice, just in case you are finding errors in writing.
I created this for my students because I was noticing a lack of understanding of subject verb agreement in essays.
There is a reference sheet with rules for SV agreement (one page), and a practice sheet (one page). You can double side these and have students keep them in their binders for future reference.
The practice sheet requires students use their own paper, and I have included answer key for ease of grading. There are three practice sets, and each one consists of 10 questions.
I go over the rules and examples with students, and then they can work on the practice individually or with a partner.
I hope this provides some useful instruction.