Students practice adding mixed numbers with like denominators through multiple activities and answer-key examples (e.g., 4 1/5 + 3 2/5 = 7 3/5; 4 5/8 + 2 3/8 = 6 8/8). Students use visual methods to add mixed numbers by shading whole circles and fractional parts (Activity 2) and follow steps that add whole-number parts first and then fraction parts. Students are shown and instructed to use the Commutative Property to add whole numbers first (Activity 3 example: 2 2/5 + 3 1/5 = 2+3+2/5+1/5 = 5 3/5).

Students are asked to add and subtract mixed numbers with like denominators in the Skills list and in the Wrapping Up practice page, which contains many mixed-number addition and subtraction problems. In Activity 1 students shade and cross out circle diagrams to compute differences of mixed numbers with like denominators, giving visual practice with subtraction of wholes and fractional parts. In Activity 2 and its answer key students stack and regroup mixed numbers, and examples explicitly show converting a whole into fractional parts (e.g., 5 = 4 8/8) and rewriting mixed numbers to subtract.

Students practice adding fractions with like denominators in multiple places (e.g., repeated addition of 1/5 to make 4/5 and the explicit note that when adding fractions with like denominators the denominator stays the same). The lesson shows converting an improper fraction to a mixed number (6/5 → 1 1/5) and includes mixed-number problems on the Fractions Quiz (for example, 12 11/15 - 5/15 and several mixed-number addition problems). Practice worksheets require students to compute sums and differences that involve mixed numbers and like denominators.

Students solve multiple problems that require adding and subtracting mixed numbers with like denominators (e.g., the lasagna problem: 1 1/4 + 2 2/4 + 3/4 = 4 1/4; Cooking With Fractions problems showing sums like 5 and 1/3 cups and differences like 1 and 2/3 cups). Students write equations and draw pictures for mixed-number problems (What Are the Fractions? and Cooking pages) and complete sample subtraction pairs with like sixths (2 3/6 - 2 1/6 and 4 5/6 - 4 3/6). Students are prompted to note that the denominator remains the same when adding and subtracting fractions with like denominators.

The Skills list explicitly includes "Add and subtract mixed numbers with like denominators." Multiple practice and test items require students to add and subtract mixed numbers with like denominators (for example: 4 1/5 + 3 2/5 = 7 3/5; 6 7/10 - 2 4/10 = 4 3/10; 3 2/5 + 3 1/5 = 6 3/5). Two linked videos target the topic: one titled "Adding Mixed Numbers" and one titled "Subtracting Mixed Numbers," the latter noting use of regrouping to subtract mixed numbers. The Unit Review and Unit Test include word problems and assessments that require students to write equations and solve mixed-number addition and subtraction with like denominators.

The lesson lists the skill "Add and subtract fractions that have the same denominators" and provides an "Adding and Subtracting Fractions Review" worksheet with multiple problems that add and subtract fractions sharing the same denominator (for example, 7/6 + 2/6, 3/7 + 5/7, 4/15 + 7/15). The introduction explicitly models that an improper fraction (6/4) is equal to a mixed number (1 2/4 or 1 1/2), showing conversion between improper fractions and mixed-number form. The wrapping-up activity has students convert fractions to a common denominator (18) to order them, reinforcing work with equivalent forms and common denominators.

The Skills section explicitly lists "Solve problems involving addition and subtraction of fractions by using information presented in line plots." The Creating a Line Plot activity asks students to find the total weight of rabbits that weigh 2 1/4 pounds (answer: 6 3/4), which requires adding the mixed number 2 1/4 three times. The same activity asks for the difference between the heaviest and lightest rabbit (answer: 1 3/4), which requires subtracting mixed-number measurements.

Students solve recipe and measurement problems that require adding and subtracting fractional quantities and mixed numbers (e.g., combining 3 pints + 1 1/2 cups + 1 cup + 2/3 cup to get 9 1/6 cups; finding 1 1/2 cups − 2/3 cup = 5/6 cup). Students convert between units to put quantities in like units before combining them (e.g., 3 pints → 6 cups; 1 1/2 pounds → 24 ounces and then add to 1 pound to get 40 ounces). The answer keys show students producing sums and differences of mixed-number quantities in context.

Students encounter mixed-number quantities in word problems such as Maggie/Timothy/Katherine (2 pints, 5 cups, and 1 1/2 pints) where they must convert units and compute a total (answer 12 cups). Students also encounter 1.5 pounds in Yuri's purchase (2 lb, 10 oz, and 1.5 lb) and must convert and add weights to find a total in ounces (answer 66 ounces). These items require students to convert mixed or decimal quantities to a common unit and perform addition to find a total.