Number Sense is a person's ability to use and understand numbers:
1) knowing the relative values of numbers

    

For example: the number 92 has 9tens and 2 ones OR 90 + 2

2) how to use numbers to make judgments

For example: I will need about 25 cupcakes for a class party

3) how to use numbers in flexible ways when adding, subtracting, 

     multiplying or dividing

For example: I can add 15 + 12 by adding the tens first (10+10 and then the ones next 5 + 2)

4) how to develop useful strategies when counting, measuring or estimating.

For example: a reasonable estimate of cupcakes needed for a class party is 30 and not 300

“When children have daily, long-term opportunities to work (and play) with numbers, you will be continually amazed by the growth in their mathematical thinking, confidence, and enthusiasm about mathematics. By helping your children develop number sense, especially in the context of problem solving, you are helping them believe in themselves as mathematicians.”

Below is an example of a simple number sense activity you can do with your child.  You can adjust the numbers shown to fit your child’s grade (single digits for K and 1 and triple and higher digits for 3 and 4).

Activity	Books	Apps
How Far Away? 1. Sketch a number line and locate on it 0, 25, 50, 75, 100 2. Create all the possible  two-digit numbers using the three digits that were rolled: 2, 6, 3. 3. Place the numbers on the number line using 0, 25, 50, 75, and 100 as benchmark numbers. 4. Determine how far away each number is from 100?	Math Potatoes: Mind-stretching Brain Food by Greg Tang and Harry Briggs(Jul 1, 2005) Bedtime Math: A Fun Excuse to Stay Up LateHardcover– June 25, 2013 by Laura Overdeck (Author), Jim Paillot(Illustrator) Spaghetti And Meatballs For All! (Scholastic Bookshelf: Math Skills) by Marilyn Burns and Debbie Tilley	1.    Math dual 2.    Tower of Hanoi 3.    Enigma 4.    SET by enterprises inc Mastermind 5.    Kenken 6.    Slice it