Teaching Equivalence in Fractions with Unlike Denominators to 4th Graders
2 x 2= 4
5 x 2= 10
So 2/5 times 2 on both the top and the bottom equal 4/10.
Then the teacher explains how the process of cross-multiplying works and how to to determine if fractions are equivalent to each other by using this method. The teacher would explain that if two fractions are presented as ½ and 5/10, then you multiply 1 times 10 and then multiply 5 times 2. The answers should both be 10. In this example the two fractions are equal to each other because the answer to both problems is 10. A second example would be the fractions ¾ and 2/12 and you multiply 3 times 12 and 2 times 4, these answers are not the same and so these fractions are not equivalent to each other. This is because the answers to the multiplication problems are 36 and 8.
Once the lesson is taught, the teacher will give students practice questions and problems to further secure their understanding of equivalent fractions. The following problems are examples teachers can use.
Please write an equivalent fraction for the following fractions:
Are the following fractions or numbers equivalent? If not what is the equivalent?
4/4 and 1? ______
2/3 and 4/6 ? ______
1/3 and 3/6 ? ______