# Addition and Subtraction of Fractions with Unlike Denominators

### Addition and Subtraction of Fractions

This unit is about adding and subtracting fractions with unlike denominators. Students will use models to construct their understanding of adding or subtracting amounts that are not the same size. A heavy emphasis on modeling is important. I try not to teach the “standard” steps until much later in the unit to give students time to understand the importance of equivalent fractions. They will use fraction strips, fraction circles, area models, and number lines to add and subtract fractions. This is the last piece for 5.3K- add and subtract positive rational numbers fluently. 5.4F is included in this unit, students will solve order of operation problems with fractions.

### I see you~

• struggling each week to write lesson plans that meet the rigor of the TEKS.
• searching endlessly for resources that will help kids learn math while being challenged and engaged.
• staying late everyday after school working on plans and creating everything from scratch.

You are exhausted from working with students all day,
and still have to prep, write and create.

I see you~

• SACRIFICING your time with your family and friends to ensure success for ALL of OUR Children.

### Days 1-5

Day 1: I will estimate to determine solutions to mathematical and real-world problems involving addition, subtraction.

The unit starts with an anticipation guide. The students answer 5 statements designed to help you assess what they already know, but more importantly- what are they confused about!  Estimation is a huge part of number sense. Benchmark fractions of 1/2 and 1/4 are critical to developing fraction sense.

• Play Minute to Win it! 24 addition and subtraction word problems using estimation of fractions are included!

Day 2: I will represent and solve addition and subtraction of fractions with unequal denominators referring to the same whole using objects and pictorial models.

*This day is not a direct teach. The goal is to overcome the misconception of adding or subtracting the denominators. Try not to show the math process of making common denominators. Students use fraction strips and number lines to figure out WHY they need common parts.

• 12 problem cards for Guided Practice and 12 problem cards for Mirror or SCOOT

Day 3: I will represent and solve addition and subtraction of fractions with unequal denominators referring to the same whole using objects and pictorial models.

Repeat lesson from yesterday using fraction circles instead of fractions strips! Continue to use the number lines to help find the common denominator. This will help kids see the number of parts as a name instead of a number.  Compare and Contrast the two different models- bars and circles with a Venn Diagram to help make connections and encourage Math Talk.  4 problems for adding three fractions with unlike denominators help kids find the common denominator because they can't just multiply the denominators!

• Roll and Solve using models

Day 4: I will represent and solve addition and subtraction of fractions with unequal denominators referring to the same whole using objects and pictorial models.

The AREA Model!  I love that this model can be used with almost any math concept!  In this lesson, students work with least common multiples to find the common denominator.  The area model reinforces the idea of equivalent fractions!  The amount stays the same, the parts get smaller (or larger) to give use a common denominator!

Day 5: I will represent and solve addition and subtraction of fractions with unequal denominators referring to the same whole using objects and pictorial models.

Students read area models that add and subtract fractions with different denominators with area models to write an expression.  Writing an expression based on a model is foundational for 5.3H!

• Write the expression SCOOT: 10 models (To make this a 20 minute activity: Make two copies on different colored cardstock, and divide the class in half!)

### Days 6-8

Day 6: I will represent and solve addition and subtraction of fractions with unequal denominators referring to the same whole using properties of operations.

Students love this game!  Mystery Challenge will have your kids searching for clues and solving addition and subtraction word problems with fractions! Theft on the High Sea will engage your students in problem solving!

Day 7: I will represent and solve addition and subtraction of fractions with unequal denominators referring to the same whole using properties of operations.  This is the last day of modeling 🙁

• Roll a Number

Day 8: I will add and subtract positive rational numbers fluently.

Great Granny's Chocolate Chip Cookie Recipes: Use the recipe to make a connection: If we were going to make both kinds of cookies, how much sugar will we need? How many more cups of flour are in peanut butter than chocolate chip? Ask students to make up a problem for their partner to solve.

•   12 practice problems for Mirror

Day 9: I will add and subtract positive rational numbers fluently.

Positive rational numbers include fractions, decimals and whole numbers. This is when Math gets fun! When numbers are in different forms, fractions or decimals, we have to make then the same in order to add or subtract. (Use the area model to show 3/10 and .3) We can make a fraction out of any decimal and a decimal can be any fraction.

Side Note: Encourage students to change the decimal to fraction whenever possible. It might be easier now to do it the other way- BUT ALGEBRA will happen and they need the fraction!

• 10 problem SCOOT using a map, clocks and tables.

#### October 3, 2018, Katie Miller's Creations

Day 11-13: I will simplify numerical expressions that do not involve exponents, including up to two levels of grouping.

Since this TEK has been taught multiple times, review what your class is struggling with. Remember not to change fractions to decimals! They need to practice with fractions for Algebra readiness!

• Roll 4 Luck: 10 order of operations with fractions problems