As students learn to recognize fractions in objects and on number lines, reviewing parts of whole numbers will introduce them to the concepts of adding and subtracting fractions. Provide the students with two circles of the same size, a full circle representing the number one and another circle cut into eight even slices. The students will experiment by adding and subtracting combinations of the slices that make up a whole circle. They can also work on a fraction search by finding two or three fractions on a word-search style worksheet that combine to make the number one.
Before adding and subtracting fractions, students must learn to only add and subtract numerators while leaving common denominators alone. Illustrate this point by comparing fraction denominators to students' favorite indestructible superheroes. Create a large fraction board including superheroes holding like denominators as the base of fractions, and give the students number cards they can use as numerators for adding and subtracting. By manipulating the numerators only, students will get the idea that like denominators remain the same.
When two fractions have different denominators, students need to alter the fractions to have the lowest common denominators before adding or subtracting the numerators. Start with simple fractions, such as 1/2 and 1/4 and ask students to list the first five multiples of both numbers to find the least common multiple. Provide students with word problems, worksheets and manipulatives that allow them to practice finding lowest common denominators in a variety of ways.
Before adding or subtracting mixed numbers, students need to convert them into improper fractions. Introduce students to mixed number fractions with a hidden picture puzzle. Students can find mixed numbers in a picnic scene by spotting mixed proportions of different items, such as sliced pies, broken bats and cans of soda. After reviewing mixed numbers with the class, give students pie shapes and counting cubes and allow them to practice counting the total pieces in mixed numbers and transforming them to improper fractions.