There are many online resources that can help children learn to order fractions from least to greatest, including Khan Academy, Math is Fun and Math Goodies. Khan Academy has a video that explains how to order fractions and practice exercises that student can try to master this skill. Similarly, Math Goodies shows how to order fractions with simple examples.
Math is Fun teaches students how to compare two fractions to find the greater of the two. A typical example of ordering fractions is ordering 1/6, 4/9 and 3/12 from least to greatest. The first step is to express these fractions with a common denominator as 6/36, 16/36 and 9/36. The next step is to look at the numerators and list them form lowest to greatest, which is 6/36