How many sentences should there be in a paragraph for student 5th grade?

There's no magic number of sentences for a 5th-grade paragraph. A good paragraph should focus on a single topic and develop that idea completely. The number of sentences needed to do this will vary depending on the complexity of the idea and the writer's style.

A good rule of thumb is 3-7 sentences. Shorter paragraphs are fine, especially if the idea is simple. Longer paragraphs might be okay if the topic is complex, but they should be carefully constructed to maintain coherence and avoid rambling. More important than sentence count is that the sentences flow logically and support the main idea. A paragraph with two well-developed sentences might be better than one with five poorly connected sentences.