Lessons 6 and 7 introduce students to metric weight measured in kilograms and grams. Students learn to use digital scales as they explore these weights. They begin by holding a kilogram weight to kinesthetically understand its feel. Then, groups of students work with scales to add rice to clear plastic zippered bags until the bags reach a weight of 1 kilogram. Once the bags are made, students decompose them using ten-frames. They understand the quantity within 1 square of the ten-frame as an estimation of 100 grams. Upon that square they overlay another ten-frame, “zooming in” to estimate 10 grams. In Lesson 8, students use scales to measure the weight of objects precisely, and then use those measurements to solve one-step word problems given in the same units. Word problems require students to add, subtract, multiply, and divide. Students apply estimation skills from Lesson 7 to reason about their solutions. In Lessons 9 and 10, students measure liquid volume in liters using beakers and the vertical number line. This experience lends itself to previewing the concept and language of rounding: students might estimate, for example, a given quantity as halfway between 1 and 2, or nearer to 2. Students use smaller containers to decompose 1 liter and reason about its size. Lesson 11 presents students with mixed practice adding, subtracting, multiplying, and dividing to find solutions to problems involving grams, kilograms, and liters.