Grouping Tens and Ones Lesson for Second Grade

Mar 2, 2011
Michael Quadro

Base Ten Blocks - Assessment Services, Inc.

In this lesson, students will demonstrate the ability of grouping two-digit numbers into tens and ones by using base ten blocks.

California 2nd Grade Math Content Standards, 1.0, 1.1, 1.2 and 1.3.

1. Ask your class these series of questions:

What is a one-digit number?
What is a two-digit number?
Is something different about these two kinds of numbers?
Can two-digit numbers do something that one-digit numbers can’t? (two-digit numbers can be broken into the tens group and the ones group)

2. Pose this math problem to your class:

My birthday is coming up, and I’m going to have a big party. It’s a surprise, so don’t tell anybody. I’m going to invite 40 people. I have four tables for all my guests to sit. And this is where I get kind of confused, maybe you all could help me out. I want to have the same number of people sitting at each table, but I don’t know how many people can I put at each table so all the tables have the same number of people?

3. Write on your classroom whiteboard:

Write the number forty to represent the forty guest.
Draw four circles on the board to represent the tables.
Put random tally marks inside the tables. Get a little funny by saying, "I'll put my Dad here, Auntie June over here, my dog Jack here, etc....So I have four guests at this table, seven guests at this table, I'm still not sure how many guest should be sitting at the tables?"
Elicit the answer, 10 people can be sitting at each table.
How did you figure that out?
We figured out that the number 40 has four groups of tens. We now know that 10+10+10+10=40.
Make a tens and ones chart on the board.
How many groups of tens are in 20, 30 and 50?
Can we count to one hundred by tens?

4. Introduce base ten blocks to your class:

Say to your class, "I’m going to show you a tool that can be used to help you figure out how to group two digit numbers into tens and ones. It’s called base ten blocks." (If you don't have base ten blocks, draw base ten blocks on the whiteboard.)
Explain the difference between the rods and cubes.
Introduce a new problem, "Man, I just realized another problem about my party. I have 40 guests coming, but I only have 36 party favors to give to them. How many people won’t get a party favor?"
Elicit the number 4.
Write on the whiteboard 40-36=4.
Say, "I can use the base ten blocks to help me out with this problem."
Demonstrate how to use the base ten blocks to solve 40-36=4.

5. Give your class some independent practice:

Put students into groups.
Give each group a set of blocks.
Write two-digit numbers on the board and have them represent the numbers using the blocks.
If you don't have any base ten. Give each student some paper to draw the representations of the numbers.

6. Monitor your class to see how they are progressing:

Be a facilitator.
Give your students time to figure out the base ten blocks on their own before you jump into correcting mistakes.
You be the judge of your class.

Michael Quadro - Michael Quadro is an educator, musician, and freelance writer in the SF Bay Area. Michael began his writing career in 2010 and has been ...