# How is the F1 score calculated in a question-answering system?

I have an NLP model for answer-extraction. So, basically, I have a paragraph and a question as input, and my model extracts the span of the paragraph that corresponds to the answer to the question.

I need to know how to compute the F1 score for such models. It is the standard metric (along with Exact Match) used in the literature to evaluate question-answering systems.