Reddit reviews Teaching Student-Centered Mathematics: Developmentally Appropriate Instruction for Grades 3-5 (Volume II) (2nd Edition) (Teaching Student-Centered Mathematics Series)

Here are some activities courtesy of John Van de Walle:

On the board write a collection of 8 to 10 factions. A few should be greater than 1, with the others ranging from 0 to 1. Let students sort the fractions into three groups: those close to 0, close to 1/2, and close to 1. For those close to 1/2, have them decide if the fraction is more or less than 1/2. The difficulty of this task largely depends on the fractions. The first time you try this, use fractions such as 1/20, 53/100, or 9/10 that are very close to the three benchmarks. On subsequent days, use fractions with most of the denominators less than 20. You might include one or two fractions such as 2/8 or 3/4 that are exactly in between the benchmarks. As usual, require explanations for each fraction.

Have students name a fraction that is close to 1 but not more than 1. Next, have them name another fraction that is even closer to 1 than that. For the second response, they have to explain why they believe the fraction is closer to 1 than the previous fraction. Continue for several fractions in the same manner, each one being closer to 1 than the previous fraction. Similarly, try close to 0 or even close to 1/2 (either under or over). The first several times you try this activity, let the students use models to help with their thinking. Later, see how well their explanations work when they cannot use models or drawings. Focus discussions on the relative size of fractional parts.

Draw a picture of a shape with a portion shaded, or a number line with an "x" on it. Have each student write down a fraction that he or she thinks is a good estimate of the amount shown (or the indicated mark on the number line). Listen without judgment to the ideas of several students and discuss with them why any particular estimate might be a good one. There is no single correct answer, but estimates should be "in the ballpark". If children have difficulty coming up with an estimate, ask if they think the amount is closer to 0, 1/2, or 1.

These activities are all from this book: http://www.amazon.com/Teaching-Student-Centered-Mathematics-Developmentally-Appropriate/dp/0132824876/ref=sr_1_6?ie=UTF8&qid=1458582087&sr=8-6&keywords=john+a+van+de+walle which has been a big help to me when planning math lessons.