Math Talks/20 Days of Number Sense

If you have read my other posts, you will know that I have been on a journey to improve my mathematics instruction for a few years now.  I have been researching the latest and greatest practices and trying to implement them into my classroom while continuing to be as true as possible to our district choice of math text books.

I have found that the more I know, the more I realize I don’t know.  However, the good news is that there are many math educators that are putting up content on their websites for free.  Yes! Free!  I was amazed when I began to discover this, as it has been the trend with Teachers Pay Teachers website, what used to be shared is now for a fee.  I am not knocking TPT, but this was a refreshing change.

I began hearing about math talks.  These are about 15 minutes whole class/small group discussion on some area of mathematics.  My target for these talks are aimed at  mostly  developing the students’ number sense, as this is an area I feel they need the most help with.  I use a variety of sources for my math talks, as well as make up many of my own.  As I mentioned above, there are many free sites to help teachers of all levels with this.

Once such site is created by Steve Wyborney.  I stumbled across his site last year and fell in love with everything about it.  My thirds love everything about it!  We are currently participating in his 20 days of number sense and rich math talk.  While we have done a version of each of the activities, the students are loving knowing we are in a 20 day boot camp.  For each activity, students use a white board and mark down their answer and their strategy.  If there is time, they try the problem another way. They can also have discussions within their group (my students sit in groups of three) and then we discuss as a whole class.


We started with 5 days of this activity..the estimation clipboard.  In this activity, students make a guess on say how many balls are in a glass.  They they find out the exact number in the glass. In the next slide, they are given the same glass with more or less balls in it.  Students need to use the information from the first slide to help them determine the answer.  There are four different pictures for each activity, each with a different amount of balls. 

The next 5 days, we did the splat series.  Students counted dots outside the splat.  They then have to figure out how many are

img_4453underneath the splat, to get to the targeted number.  Students strengthen their skill of subitizing (which is being able to look at number without counting) to determine how many dots are showing. They also use addition and subtraction to figure out the hidden number.

We then moved on to estimysteries. Students make a guess on how many in a container. They are then given clues.  They can revise their answers.  Clues can be such as there is not a 1 in the img_4454.jpgtens place.  The number is even, etc.

The very last section is the cube activity (see below).  Students need to count how many cubes are in a different picture.  They are then challenged to look and see if they can count it a different way.  This was actually the only time I thought to take pictures of the students’ work.


I am very grateful for Steve Wyborney and the amazing work he is doing on his website and allowing us to access it for free.  It has made a tremendous difference in my students’ number sense. They are making better estimations, they are able to subitize more quickly and accurately.  It has helped their addition, and place value.  It has allowed them to problem solve, defend their choices and most importantly feel like a mathematician.  The amount my students have grown from this is really immeasurable.

Just 15 minutes a day with a math talk has greatly changed my mathematics classroom.

Author: kathyiwanicki

Classroom teacher in year 32..Just trying to get better every day!

6 thoughts on “Math Talks/20 Days of Number Sense”

  1. This was a game-changer with my 2nd graders. I’m really looking forward to implementing t with my 3rd graders this year


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