This Instructional Activity is a part of the Lesson 17, Unit 5, Grade 6. English language learners may not recognize the word surface; take this time to explain what surface area means. Demonstrate that surface is the upper or outer part of something, like the top of a desk. Therefore, surface area is the area of all the faces, including the bases of a three-dimensional figure. Use the diagram below to discuss nets and surface area. Examine the net on the left and the three-dimensional figure on the right.