This lesson takes a constructivist approach to the concept of a "tens place" and a "ones place". Students create orders using tens and ones, and then keep track of how many ten strips they needed and how many single stickers. When we debrief this activity, we will "look for and make use of structure" (MP7). Students will look for the pattern and notice that when we write the number, the digit that tells us the number of tens remains constant.
Today we are going to look closely at building a number with tens and ones again but we are going to see what patterns we notice in these numbers. Paying close attention to what the number tells us about the number of tens and ones will help us build even bigger numbers later in the year.
Objective: How does the number help me know how to build a number with tens and ones?
I'll have an “order form” chart on chart paper (see attached anchor chart!)
I'll start by setting the scene and explaining the materials:
For ten strips and singles, see attached documents!
The first order that came in this week is 15. We have to show how we fill that order with our strips of 10 and ones.
Partner Talk: We need to show 15 with tens and ones. How can I do this using tens and ones?
I'll show students how to record it on the chart.
Think Aloud: "I see that there was 1 ten and 5 ones. Hmm…that is interesting. We write 15 with a 1 and a 5. Here the number is 1 ten and 5 ones."
Partner Talk: Let’s do another one. Show your partner the next order. This person ordered 18 stickers. How can you show 18 with tens and ones?
I'll restate: So we had 1 ten, 8 ones. Let me write that in my chart. Wait! 18 is a 1 and an 8, we built the number 18 with 1 ten and 8 ones. Kind of like 15! A 1 and a 5, 1 ten and 5 ones.
Present new problem: On your paper, show the order for 40. How many tens? How many ones?
See the attached Sticker Chart for the anchor chart we made.
Student Work Time: Students work on making 40 using the ten strips and singles.
Share Time: This share time is focused on the structure of the number. This promotes students noticing and making use of structure, a key mathematical practice standard within the Common Core.
I'll start by having a few groups model how they made 40.
Now let’s look at the other side of the numbers.
Think Aloud: These numbers are telling us how to build them! In each number, the number on the right told us how many ones. That is the ones place. The number on the left told us how many tens, that is the tens place.
(I'll do a few more numbers if time)
Goals: Students may need to count the stickers by 1s to create the orders.
Push Question: If students are counting by 1s, have them count all by 1s and then ask: “Is there a faster way we could count the strip of stickers? How many are on that strip? 10! How could we count all the tens faster? Let’s try it.”
Goals: Students start to use the structure of the number consistently. Students may say “I just know it needs 3 tens because the number says so”. Need to be pushed on WHY.
Goals: These students get the Group C sheet, which has harder numbers (Single digit and 2 digit numbers off the decade). See if these students can use what they know about the tens and ones places to help them build the numbers.
See attached documents for materials and independent practice sheets.
Today we wanted to see how the number helps us know how many tens and ones we need to build it.
Let’s add a few more numbers to our chart. I bet you can use how we write the number to help us show the order!