## Number & Operations – Fractions – 4th Grade

#### Build fractions from unit fractions.

CCSS.Math.Content.4.NF.B.3.c
Add and subtract mixed numbers with like denominators, e.g., by replacing each mixed number with an equivalent fraction, and/or by using properties of operations and the relationship between addition and subtraction.

Teacher Notes
Knowing how do you decompose an improper fraction into a sum of a whole number and a number less than 1 is the first step of understanding a mixed number.   You should start with using  visual models to build understanding.  When adding and subtracting mixed numbers we are joining or separating parts within the same whole.

Student Knowledge Goals
I know that mixed numbers can be written as fractions.
I can use the properties of operations to solve addition and subtraction problems involving mixed numbers with like denominators.
I can use what I know about whole number addition and subtraction to solve problems with mixed numbers.
I can use what I know about adding and subtracting fractions to solve problems with mixed numbers.
I know that mixed numbers can be combined or separated (composed and decomposed).
I can use a variety of strategies for adding and subtracting mixed numbers.
I understand that mixed numbers can be combined or separated (composed and decomposed).

Vocabulary
improper fraction
mixed number

Lessons
Engage NY Module 5 F-29 – Estimate sums and differences using benchmark numbers.
Engage NY Module 5 F-30 - Add a mixed number and a fraction.
Engage NY Module 5 F-31 - Add mixed numbers.
Engage NY Module 5 F-32 - Subtract a fraction from a mixed number.
Engage NY Module 5 F-33 – Subtract a mixed number from a mixed number.
Engage NY Module 5 F-34 - Subtract mixed numbers.

Student Video Lessons
Virtual Nerd - Understand a fraction a/b with a > 1 as a sum of fractions 1/b
Study Jams - Adding and Subtract mixed numbers

Online Problems and Assessments
Khan Academy – Questions and Video Lessons
Add and subtract mixed numbers with like denominators

Online Games