In this video the tutor shows how to add and subtract monomials. He says that to add or subtract monomials they have to be similar terms. Similar terms are those that have same variables and equal exponents to the variables. He shows how to do this using illustrative diagrams and solves a couple of sample problems. He adds a few monomials with similar terms and also explains how to subtract a few monomials. This video gives an introduction to similar terms and how to add and subtract monomials.