# Where Can I Find It

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## Objective

SWBAT read a 2 digit number, identify the digit in the ten's and one's place and locate the numbers on the number line.

#### Big Idea

The Common Core standard is for students to add and subtract numbers within 100 fluently using models. They must understand the place value to build the models.

## Warming Up

10 minutes

I am starting with the Ten's Partner Rhyme again today. It may seem repetitive, but research suggests that students need to hear things many times before they can use it so I will repeat it again today, and then every couple of days after this.

I bring out the bundles of 10 into bundles of 100 papers from a previous lesson Student Work - Bundles of 10 into 100. I ask students to write the number shown by 2 bundles of 100. I have a volunteer write the number on the board. We read the number and talk about the fact that we say 2 (2 bundles) and then the word hundred (because the two is in the hundred's place). I ask students if we have any bundles of ten? (no) so we put the zero in to tell us that. Do we have any single ones? (no) so we must put a zero in for that as well, giving us 2  0    0 . We repeat the exercise with 4 bundles of 100. Again I talk about the use of the zero to tell us we have no bundles of ten and no single ones.

Next I show the 4 bundles of 100 and 3 bundles of ten and ask for a volunteer to write the number on the board. I remind students that we have no single 1s without a bundle so we need to put a zero in the number to tell us that we have no single ones. We read the number 430. We break it apart into 4 (bundles of 100) the word tells us hundred, 3 (bundles of ten) and 0 ones. We put the last two digits together and say 30.

I ask which is more, the 4 bundles of 100 and 3 bundles of ten or the 2 bundles of 100? How do you know? I take several suggestions of how they know. (There are more bundles of 100, there are more bundles of 10, etc.)

I tell students that again today, they will be in their work groups to explore more about larger numbers.

I give them a quick stretch break before they listen to my directions for the remainder of math.

## Teaching The Lesson

35 minutes

Now that students have had a stretch break I ask them to join me on the rug. I bring up a blank line on the Smart Board (or other display). I mark the line in equal increments. I ask students what the line makes them think of? (number line) What is missing? (numbers). I ask students how they might use this line to add 17 + 3? (There are not enough increments to make 20). I let students come up and show me the strategy they might use to solve the problem. We talk about how we can place a number on the line and then count up or back the number of spaces and find our answer.

I repeat the lesson with the problem 25 - 5.

I ask students if the number line could help me find which is bigger or smaller if I had the numbers 34 and 42. Again, I use a blank line and ask students to show me their thinking. We talk about if we look at the ten's digit we can place the numbers on the line, or fill in by counting from one to the other. If we count up, our numbers would go up in value. If we count back, our numbers would go down in value.

I tell students that they will be rotating through centers today practicing using, finding and naming numbers. I divide the students into the same groups I had yesterday and tell them that the directions for each center are at the center. I will rotate around at the beginning to make sure students understand what is expected of them.

1. Students are given a large blank number line that is taped to the table and covered with erasable laminate. There are number cards face down on the table. Students turn over 2 cards and place the numbers on the number line in the places they would be found. They then use the paper alligator mouth (<>) to show which is greater and which is smaller. One student reads the number sentence aloud to the group. They repeat the process with other cards.

2. Students are given number sentences to solve on a large blank number line (similar to above). They use a small plastic frog and place him on a space where they choose the first number to be. They hop him the number of spaces forward or back and then count to the answer. (This can be individualized by giving students higher numbers if they are ready for them. I have 3 sets of equations for the three groups.)

3. Students are given an individual hundred's chart (number grid). One student draws a card and calls out a number. Everyone finds the number and puts a colored chip on that number. The next student draws a card and calls out a second number. The students put a second colored chip on that number. The third student must say which number is greater or larger. (If the numbers are 24 and 56. The third student would say 56 is greater than 24.) The process is then repeated with new numbers. (This can be individualized by having some number grids in the 300s or above. These groups would be dealing with the larger numbers.)

## Closing

10 minutes

At the end of math centers, I bring students together to talk about what they noticed about the number line today. I ask students to comment on how they like using a number line that had no numbers on it, whether it would be a good tool for them to use if they needed to figure something out. Using The Number Line

Students noticed many things about the number line. Some of the students always counted by ones, others figured out they could count by 5s or 10s to get to their answer. The students were modeling with mathematics using the number line to help them solve problems (MP4). They also saw the structure of the number line as a tool to help them figure out the answer (MP7).

The importance here is for students to realize that a blank number line is a tool that they can use on their own when they need to solve a problem. Students need to be provided with a variety of math support tools that they are comfortable with and can easily create when they are faced with a problem to solve. This encourages independent thinking and learning.