The lesson itself takes a while for students to complete because of level of difficulty, not length of questions (MP1). Since I know students need time to work and talk I would make the introduction short. Highlight the seventh grade standards that are being reviewed today:
7.NS.1 Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers; represent addition and subtraction on a horizontal or vertical number line diagram.
7.NS.2 Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers.
Then, brainstorm what it means to be a rational number. Make it clear that today is about reviewing operations with fractions as we use fractions in equations.