November 2019 - Down River Resources
Students that have "number sense" can solve a problem in a variety of ways. Flexibility with numbers is what helps these students show their sensational number sense.

Researchers have linked good number sense with skills observed in students proficient in the following mathematical activities: mental calculation, computational estimation, judging the relative magnitude of numbers, recognizing part-whole relationships and place value concepts; and problem solving.

Most Number Sense routines take an average of about 10 minutes and are incorporated at the beginning of the math block.

There's four common Number Sense routines that are used daily in elementary math classrooms across the world. Okay, friend, here's what you've been waiting for...

## The Best Number Sense Routines for the Elementary Math Classroom

### 1. Which One Doesn't Belong? (WODB)

Which One Doesn’t Belong? is a routine that revolves around an thoughtfully designed four image set. Each of the quadrants can be a correct answer to the question “Which one doesn’t belong?”

Because all their answers are right answers, students naturally shift their focus to justifications and arguments based on properties. A teacher can facilitate rich discussions and teach mathematical argumentation using Which One Doesn’t Belong? You can use this routine to listen closely and respectfully to students’ ideas.

### Resources for Which One Doesn't Belong?

Guiding Questions: What do you notice? What makes all the items alike? What makes them different? Which one doesn’t belong? Can you share your reasoning to justify your answer?

Image Website: http://wodb.ca/index.html

### 2. Number Talks

Number talks are brief discussions (5–15 minutes) that focus on student solutions for a single, carefully chosen mental math computation problem or a number string, a series of related problems. Students share their different mental math processes aloud while the teacher records their thinking visually on a chart or board.

### Resources for Number Talks

Guiding Questions: How did you solve that? Explain why you did that? How did that help you solve the problem?

Book Recommendations: This is my FAVORITE book for Number Talks (by Sherry Parrish) and is appropriate for all elementary grades.

I really appreciate the myriad of suggest problems to use to help students practice specific strategies. They are all laid out in this book. It's like a huge resource bank for Number Talks. There's also video footage of variety of Number Talks, which helpful for newbies to this routine.

There is another series of book for upper grades that I recommend: Making Number Talks Matter: Developing Mathematical Practices and Deepening Understanding, Grades 3-10. I have found valuable information in this book, but has less examples than the first text I recommended. It is typically less expensive that Sherry's book.

Estimation is a skill that occurs naturally but one that needs to be nurtured and massaged as the child's brain develops. Think: use or lose it. Estimating a quantity weaves in mental computations that require problem solving and critical thinking.There are a variety of estimation tasks that students can engage in including physical models and virtual models.

The most common estimation task for grades K-2 is an estimation jar. Fill a jar with similar objects (examples: cereal, marbles, mini erasers, etc.). Have students take one scoop out of the jar. Then, ask students to estimate how many scoops it will take to empty the jar. Record students' thinking and responses.

Website Recommendation

Estimation 180 is best for upper elementary math. Estimation 180 provides students with opportunities to strengthen their number sense and mathematical thinking through the use of engaging visuals and rich discourse. The visuals at Estimation 180 allow students to engage in mathematical conversations where students are encouraged to support their mathematical claims with evidence and reasoning.

### 4. Other Number Sense Routines

This is a broad category for every other Number Sense routine.

The most popular books for these routines are Number Sense Routines (see below for links).

### Resources for Other Number Sense Routines

Book Recommendations: These are two excellent books that help teachers understand the learning trajectories for the number sense routines.

Find the primary book here: Number Sense Routines: Building Numerical Literacy Every Day in Grades K-3.

Find the upper elementary book here: Number Sense Routines: Building Mathematical Understanding Every Day in Grades 3-5,

I hope this list of Number Sense routines and suggested resources gets you thinking about implementing OR diversifying your Number Sense routine in your classroom.

What number sense routines do you currently use in your classroom?