Numbers in the teens...they start with a 1!

We've been doing lots of study on teen numbers in math these last few months. Teen numbers are tricky for kindergarteners. Unlike the other double digit numbers, whose name matches the order that you need to write their digits (for example "forty-two is written "4-2" and "sixty-two is written "6-2") the teen numbers are reversed. You say the second digit first when you speak the number out loud! For example, "sixteen" is actually written "1-6," even though you say the word "six" first. Thus, many kindergarteners read and write their teen numbers backwards, even when they can write all the other numbers correctly.

We've been watching this video every day during math to try to remember that teen numbers always start with a 1. We also play lots of games, like the second video below, to help emphasize that teen numbers are made up of one group of ten, and some ones. This is an important first step in understanding place value in early math.

Here is the song:

And here is a game called Critter Junction that we played today to practice place value:

Here are some more photos of us doing math lately!

Practicing one-to-one correspondence with numbers

Subtraction with Pete the Cat!

We read the book "Pete the Cat and His Four Groovy Buttons"

Counting by tens

Making teen numbers

Math lately

We have been delving into lots of new concepts in math this trimester! Here are some pictures of what we are studying below. 

We are continuing to study teen numbers, emphasizing that all teen numbers (the numbers 11-19) are one ten plus some more ones (for example, 12 is 10 + 2 and 14 is 10 + 4). Here are two kindergarteners using ten sticks and one cubes to make teen numbers.

Figuring out partners of a number is another big push in kindergarten. This is also called "decomposing" a number. It's just a way of seeing how a number can be broken down into smaller parts. For example, 5 can be broken down into 4+1, 3+2, and 5+0. Here are some games the kids have been playing to practice the ways to make a number:

We also have time during math for free play in the block area. Kids learn a lot from playing with blocks and other building toys like Lincoln logs. It's a great way to improve spatial-visual skills, as well as practice cooperative play. Check out these creations!

Last, we have begun to explore 3D shapes (also called solid shapes). Kids love to play, build and sort with these shapes. We are starting to define their characteristics and relate them to 2D, or flat, shapes. For example, a cube has six sides, but each side is made up of a square, which has four sides of equal length.

The tricky teen numbers

We've been studying teen numbers since the beginning of the school year. Teen numbers, which are the numbers 11 through 19, are particularly tricky for kindergarteners (and anyone new to the English language) because their names are confusing. For all the other double digit numbers, we say the name of the tens place first, e.g. "35" is pronounced thirty-five, since the three comes first, "62" is pronounced sixty-two since the six comes first, etc. But for numbers 11-19, you say the number in the ones place first! "Four-teen" actually means that a one comes first, instead of a four, like the name indicates. Since the names can be so confusing, it's important to spend a long time studying them.

Teen numbers are also important because they are the first introduction to place value and our base-ten number system. The biggest message I try to pass onto the kindergarteners is the understanding that a teen number is made up of one ten and some ones. For example, eleven is made up of 1 ten + 1 one. Fourteen is made up of 1 ten + 4 ones.

We explore the teen numbers in many ways throughout the kindergarten year, so that everyone develops a good sense of what a teen number is by the time they reach first grade. Here are some of our explorations!

Exploring what a teen number is
This was our introduction to really understanding that a teen number is made up of ten and some ones. The kids had their own boards that looked similar to this so they could portray the teen number in a more hands-on way.

Snowman Punch

Each set of snowmen displayed a teen number. The kids had to find the right number written next to the snowmen, and use a hole puncher to punch the right one! Let me tell you, learning to use the hole punch was way more challenging than finding the right teen number.

Teen Number Match Up
Each kindergartener was given a teen number, represented either in digits or ten frames. They then had to roam around and find their partner who had the same number.

Teen Number Dance
This is one of my all-time favorite math games. After putting all the chairs in a circle, I turn on the wordless version of some terrible pop song that is really fun to dance to, and we dance around until the music stops. When the music stops, the kids have to race to a chair and begin counting out the number of pennies written on the piggy bank above. You've never seen a group of kids so motivated to count!

This month we are delving into decomposing numbers - particularly the all-important number 10!

Math is magnificent

One of my goals as a kindergarten teacher is to give our kids a really good, solid understanding of number sense and -- just as importantly -- to have fun with math. The U.S. lags behind in math scores compared to the rest of the world, and there is a large gap between how boys and girls perform on math skills when they are older. While the reasons for those gaps are complicated and controversial, I do think that teachers can fight against these trends by helping kids learn to love math, not be intimidated by it. Here are some examples of what we've been doing in math lately - both to help develop number sense, and to have fun doing math!

How Big is a King's Foot? Using Standard and Non-Standard Measurement

We started off by reading the book How Big is a King's Foot? which is the story of a long ago king who ordered a bed to be made for his queen. Unfortunately, he told the carpenter to make it three feet wide and six feet long - but the king's foot happened to be much larger than the carpenter's foot, and the bed turned out way too small! So to avoid this problem, to this day, we use a standard "king's foot" to measure everything (aka 12 inches).

To help understand how big a "king's foot" is, each kindergartener got a ruler and searched the classroom for things that were approximately one foot. This was their first time using a ruler so we didn't worry about precise measurement - estimation is also an important math skill. Then we recorded the items that we found.

How Big are We?

The next day, we took the same ruler and measured our friends! This was definitely more challenging, since it required holding the ruler up to their leg, then putting our finger at the end of the ruler and moving the ruler up without moving our anchor finger. The kids were fascinated to know they were three or four feet tall. And every now and then someone yelled "He's seven feet tall!!" Needless to say measuring is a skill we will revisit many times...!

Teen Number Dance with Pennies

Our favorite math activity this week came after we began learning about the penny. I learned about a game that combines teen numbers, pennies, and dancing, so of course had to try it. After lining up chairs in a circle, I put on a kid-friendly dance song, and everyone danced in their most adorable way. Then when the music stopped, they had to find a chair, each of which were equipped with a piggy bank with a teen number on it. For example, the piggy bank might say "17¢" or "12¢." When they found a chair, they needed to count out that many pennies and put them in the piggy bank! 

Here we are dancing...Popular dance moves include the disco and the Egyptian.

When the music stops, start counting!

It was amazing, because you could have heard a pin drop while they were counting, they were so into it!

And then, back to dancing!