100s Chart Math: Creating a Class Chart

I love teaching with a 100s chart. For those of you who do not know what a 100s chart is- it is basically a grid with 100 spaces numbered 1-100.  There are all different kinds out there- you can buy them or create them yourself.

Here is one I created:

You can walk into almost any classroom and see a 100s chart of one kind or another hanging on the wall.  If you walk into my classroom, you will see a 100s chart created by my students.  I have my students create our 100s chart so they understand how it “came to be” and how it works.

I start with a piece of poster board and 100 squares of papers. I use a glue stick and a ruler to create 10 rows of 10 squares.

Then I add a title and cover it with contact paper (or you can laminate it).

Now the 100s chart is ready to go!

* * * * * * *

Once the chart is ready to be used in the classroom (or homeschool), I present it to the class and have them make a few guesses as to what it may be. Oh, and I cover the title before doing this. 🙂

I then write the numbers 1 and 2 on the chart using a blue dry erase markers and ask the children to predict what number comes next.  We continue using the blue marker until we get to the space for the 5 when we change to a red marker.  I simply have this happen without explaining my reasons to the class. As we continue on, the reason will become clear.  We then switch back to the blue marker and this time, I call students to come up to the chart and fill in the numbers. When we get to the space for number 10, I make a big deal about changing the color of the marker and have the student write the  number 10 in red. We continue on this way until we get to the number 20. Usually by this time someone has figured out that we change colors for the counts by 5s (5, 10, 15, 20 etc are in red instead of blue).

As each student comes up to write a number on the chart, I ask them to give me two mathematical reasons why they put the number where they did.  For example, if a child put 17 in the chart above, his reasons might be:

17 is one more than 16.

17 comes after 16.

17 is three less than 20.

17 is ten more than 7.

17 is ten less than 27.

Often times students like to say something like, I put 98 because that is how old my Uncle Bob is. While these are fun answers, I redirect the children to share a mathematical reason.  🙂

Once the chart is complete, we can use it for a variety of in class activities! Post about these activities to come so stay tuned!

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