Base ten blocks are a great tool to use to count sets of ten, but you can really use a lot of different manipulatives for this task. Unifix cubes are great because they can be shown as ones and then snapped together to create a set of ten. Also, I have used stir straws (for coffee) and used a rubber band to group them together into sets of tens. The most important thing is to have enough supplies for every student to be able to group and count to 120. My goal will be for them to see there is the same amount (10) in every bundle and then to count those sets. We will practice two different ways: counting sets of tens by ones to understand the digit in the tens place, then counting them by tens to understand the value of those digits.
Students show me 1 set of ten on your desk. Put the extra on your name plate. Now, let's count the sets together; 1 ... How many sets of tens do we have? (1 set of ten)
Now let's see what value 1 ten has. Let's count by tens. As we count the bundles slide them across your desk (your making a one to one match as they count). (10)
So what is the value of 1 ten? (10)
I will continue with this until we have completed every number 10-90. I want them to focus on counting sets of tens. This provides them with a concrete tool to count with and be able to see how the ones are bundled into groups of tens.
I will have my students reviewing what a group of ten is and then seeing the value of multiple groups of ten (for example, that 6 tens equals 60) (1.NBT.B.2c). Students will begin to identify the decade numbers and know that, when objects are grouped into 10, 20, ..., 90, there are no leftover ones in the ones place. It is not enough for my students to learn to count by tens. I need them to identify the values behind those numbers. This will require very solid concrete experiences for students to begin forming the abstract understanding of groups of ten actually representing a certain quantity (MP2).
I have a program loaded on my computer from my district adopted math program that provides etools for us to practice using virtual manipulatives on the Smart Board. I use it for different lessons, and it really engages my students in what we are studying. They always love the opportunity to interact with technology and have their own chance to touch the Smart Board. If you do not have your own virtual tools, you can go here to access a free set of virtual tools that you can open up on your Smart Board. I will load our base ten blocks and have my students help me practice counting different amounts of tens. I will use my name sticks to call upon students and ensure everyone gets a chance to answer a question about the digits in the tens place and the values that these numbers represent. Also, I will keep an eye out for students who may need a challenge to count above the 9 sets of ten the First Grade standard expects.
My students will practice counting sets of tens using a worksheet. I have been teaching tens, ones, trading ones for bundles of tens, and identifying how many tens and ones in a number. I want them to practice independently counting sets of tens and finding how many tens are in a given decade number. There are many good worksheets to access over the Internet and you probably have your own district math curriculum. I wanted a worksheet that only focused on sets of tens with no leftover ones place numbers. I could have made my own, but found one quickly at this site: www.abcteach.com.
It is time to close out our lesson for today and review what we have learned.
I will be calling out quantities of tens. First, I want my students to turn to their groups and tell each other what the value of these sets of tens is. Second, I will count to 3 and everyone can blurt the answer all at once across the room.
I say: Here we go kids. What is the value of 3 sets of ten? Turn to your group and tell them with a whisper ... (Everyone should be telling their group 30) ... Okay 1, 2, 3.
I will continue with random numbers through 90.