Number Sense is the foundation for all higher-level mathematics (Feikes & Schwingendorf, 2008). When students pass or fail their mathematics courses, it is often the result of number sense, the ability to use numbers in a flexible way. Students with strong number sense understand what numbers mean, see the inter-relationships of numbers and how math concepts are connected, can perform mental math, and use symbolic representations in daily applications of math.

### Classroom activities to build Number Sense

One favorite activity is opening each class with a KenKen Puzzle. These puzzles are great for all levels of learners. I have modified the 4×4 puzzles to allow you to distribute a blank copy at the beginning of the week and display each day’s puzzle on a document camera. The KenKen folder includes brain teasers that you can display or post on a platform like Google classroom. The weekly packet has additional puzzle formats as well as answers to each puzzle as well as the Kenertainment puzzle. You can also subscribe to KenKen Classroom to receive your own weekly delivery of puzzles to use in your classroom.

### How to play KenKen

### Additional Number Sense Strategies

Use Estimation 180 to change up your entry task or give students an opportunity to chat with their peers while improving estimation skills. Conduct these estimation exercises similar to a Number Talk, asking individual students or groups of students to make an estimate and explain their thinking about why they made that particular estimate. Really encourage them to pull from their experiences or context clues to provide a sound estimation. The only rule, no guessing! After having a few students explain their thinking, view the answer as a whole class and give students time to reflect on how the most accurate estimation was determined.

### Number Talks

The following is from *Fluency Without Fear*:

One of the best methods for teaching number sense and math facts at the same time is a teaching strategy called ‘number talks’, developed by Ruth Parker and Kathy Richardson. This is an ideal short teaching activity that teachers can start lessons with or parents can do at home. It involves posing an abstract math problem such as 18 x 5 and asking students to solve the problem mentally. The teacher then collects the different methods and looks at why they work. For example a teacher may pose 18 x 5 and find that students solve the problem in these different ways:

Students love to give their different strategies and are usually completely engaged and fascinated by the different methods that emerge. Students learn mental math, they have opportunities to memorize math facts and they also develop conceptual understanding of numbers and of the arithmetic properties that are critical to success in algebra and beyond. Parents can use a similar strategy by asking for their children’s methods and discussing the different methods that can be used.

### How to conduct a Number Talk

### Dive deeper into Number Sense

Making Number Talks Matter: Developing Mathematical Practices and Deepening Understanding

Number Talks: Helping Children Build Mental Math and Computation Strategies