What are expressions and equations? What is the difference between them?
This is a free video lesson where I explain the difference between an expression and equation, give examples of both, and show how to write expressions from verbal descriptions. In a nutshell, an expression consists of letters, numbers, and operations, whereas an equation has two expressions separated by an equals sign. This video lesson is meant for grades 7-8 or pre-algebra.
See also
Working with expressions & equations — 2nd part of this lesson
Math Mammoth Grade 7 curriculum (pre-algebra)