Lesson objective: Solve more difficult problems related to combining fractions using models.

This lesson provides an opportunity for students to apply their knowledge and understanding of fractions to a real-life situation. Students are asked to find the total amount of cans donated in kilograms during each day of the school week of the food drive.

Key Concept students will use:

A base ten flat to add the fractions together because decimal fractions can be written in either fraction or decimal form using the visual model.

Skills students will use:

- Adding unit fractions (Grade 4, Unit 3)
- Understanding fraction equivalence and comparison (Grade 4, Unit 5)

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they use mathematical representations with base 10 flat models to show the amount they collected each day of the week for the canned food drive and make use of patterns within the structure of tenths and hundredths to quickly add together fractions with different denominators (only 10 and 100).

**Key vocabulary: **

- decimal
- denominator
- equivalent
- flat
- greater than
- less than
- model
- number line
- numerator
- representation
- rod
- unit
- tenths
- hundredths

**Special materials needed:**

- base 10 manipulative
- paper copies of flats
- paper copies of rods
- tiles