In previous lessons, students have used their understanding of fraction equivalence to compare fractions and solve problems. The purpose of this activity is to practice solving addition and subtraction problems involving decimal fractions (MP2). Students use what they know about equivalent fractions and the relationship between 10 and 100 to add tenths and hundredths.

• Invite previously identified students to share how they solved the problems.
• “¿En qué se parecen resolver estos problemas y resolver los problemas de las lecciones anteriores? ¿En qué son diferentes?” // “How was solving these problems the same as the problems we solved in previous lessons? How was it different?” (It was the same because we were adding and subtracting mixed numbers. We still looked for ways to make a new whole number when we could. We had to add up fractions that had different denominators in these problems. We had to compare with a decimal fraction written with decimal notation.)

The purpose of this activity is to create and solve addition and subtraction problems with fractions. Students first create stories to match a given value or equation and some given constraints. 

• Invite 1–2 previously identified students to share their situations for each problem.
• “¿En qué se parecen estas situaciones? ¿En qué son diferentes? ¿De qué manera cada una corresponde a las instrucciones?” // “How are these situations the same? How are they different? How does each one match the directions?”