In this lesson, students apply their understanding of place-value strategies for addition as they move from concrete to pictorial representation. They relate manipulatives to the vertical form, recording compositions as new groups below. Students use place-value language to express the action as they physically make 1 ten with 10 ones disks and 1 hundred with 10 tens disks. Working as partners, one student records each change on the vertical form step by step as the other partner moves the manipulatives.