Another Great CCSS Mathematical Practice Resource: Great Guided Math Activities
Here is a great site that expands on the meaning of the mathematical practices. It discusses exactly what the elementary standard looks like in elementary school. For example, in discussing the first practice about word problems, it show various ways to approach a problem. They give many detailed examples to get students to think deeply and critically. See two suggestions below:
You might leave off some numbers and ask children how they’d solve the problem if the numbers were known.
Or, you might keep the original numbers but drop off the question and ask what can be figured out from that information, or what questions can be answered.
Be sure to check it out!