So, I'm going to talk to you about how to make sure that your subject and your verb agree when 'each' is part of your subject. 'Each' is a pronoun, and there are three kinds of pronouns. There are singular pronouns, there are plural pronouns, and there are pronouns that kind of swing both ways. 'Each' happens to be a singular pronoun, which means that anytime you see it in a sentence, the subject is singular. There are few other pronouns like this, whenever you see words that have 'each,' 'one,' 'body,' or 'thing,' such as 'everyone,' 'everybody,' 'everything'.
Those words are singular. Let me give you an example of how this might look in a sentence. Our sentence is 'Each of the boys carry or carries his books.' So, I always begin by finding the verb in the sentence, because it's the easiest to find. In this case, the word 'carry' or 'carries' is going to be our verb or our action. So to find the subject, we look for the actor. And in this case, the actor is 'Each of the boys'.
So 'Each of the boys,' becomes our subject. We're trying to decide if this subject is singular or plural. And we see the word 'boys,' so it's very tempting to think that this is a plural subject. But don't be fooled. Notice the word 'Each,' and remember that 'each' always signifies a singular subject. So in this case,'Each of the boys,' is singular. You could read it as, 'Each one of the boys,' in this case, 'carries his books.' We need to go for the singular form of the verb 'carry'. So 'Each one of the boys carries his books.' So that's how you make sure that the subject and the verb agree when 'each' is part of the subject.