It is fitting that the reference material is sponsored by the National Science Foundation, where problem-solving is critical for not only math in the classroom but social skills, personal growth and so many aspects of the students' day, as well. It's unfortunate that traditionally those that are compelled to elementary classroom teaching tend to favor language arts rather than math and science and therefore the expansive inquiry based thinking is often missing in many classrooms for a solid problem-solving setting.
As is noted, the best practices for a teacher are to set the stage for an environment that promotes problem-solving, with good protocol established early in the year. The example offered about working together when students might have a different answer is an ...
Environment that promotes problem-solving is one of the classroom strategies discussed.