I begin with a word problem on the board. I ask students to solve the problem in their math journal notebooks.
There are 6 fish in the pond. 4 more fish swim into the pond. How many fish are there altogether?
I give students work time (2 - 3 minutes) and then ask for students to explain how they solved the problem. I take 2 to 3 different students to explain how they solved the problem.
I put a second problem on the board.
There are 8 apples in the basket. I pick 2 more. How many apples do I have now?
I give students work time and then ask for volunteers to tell how they solved the problem. I again ask several students to share their solutions.
I ask students if they notice anything about the two problems. I take a variety of suggestions and reinforce the idea that both pairs of numbers add to 10.
I ask if they can think of any other pairs that add up to 10. I record them on the board. I tell students that these are the tens partners and that they should get to know these partners.
We look at the other partners of ten, especially those that are reverse of each other, such as 8+ 2 =10 and 2 + 8 =10. What do they notice about these? (Students were introduced to fact families in first grade and may recognize that these are partners of 10. If they don't, I will remind them of the term and see if they think these represent a fact family.)
We also look at the order of the numbers. Does order in numbers make a difference? 8+2 =10 and 2 + 8 =10 we can count and see are both true. What if we try the subtraction facts for the family? 10 - 2 =8, but can I say that 8 - 2 = 10? Why not? I try to let students discover that in subtraction the larger number always has to be first or the answer will be less than zero.
I also ask if we are representing the same amount (10) using different combinations of numbers? Can you always use different numbers to show the same amount? I ask for a few examples.
Today I introduce a rhyme to go with the ten's partners. I present the rhyme on the Smart Board, but it could be projected on an overhead, or written on a chart.
We read the rhyme together several times. I ask if anyone could write a number sentence next to each part of the rhyme. Volunteers come up and write in the number sentences.
I tell students that in one of their centers today they will add the number sentences to the rhyme and illustrate each part. This will help them to remember the rhyme and the ten's partners.
I tell students to hold up 10 fingers. I show them that the ten's partners are all on their hands. If I call out 5, how many more fingers do they need to hold up to get to 10? If I hold up 8, how many? We practice this for a minute or two.
I encourage students to see that their fingers are a useful tool, especially for partners of ten. The visual for 10 is right in front of them at all times. They need only look down and they see the partner of ten. Seeing it and not having to count it is one step towards automaticity with number facts.
It is easy for adults to count by tens. If children can be taught to look for partners of tens in lists of numbers, or see things that are almost partners of ten, they are developing strategies that allow them to "just know" (which is an expression students use a lot when they know a fact automatically) a fact rather than have to count it.
Now I will individualize this lesson to meet the needs of students. The other activities they do will be in small groups. The reason for this is that some children need to really work with manipulatives to understand how the ten's partners work. Other children have a good grasp of this and can work with larger numbers.
One group of students who are still not sure of the concept of numbers that make ten (a first grade Common Core skill) will work with an adult to make tens partners. They will use snap blocks in many colors. They will all take 10 of one color and make a rod. Next they will start with 1 of one color and then make a rod of ten (the same length as the first rod) with a new color. What number partners do they see (9 +1). They will take that apart and continue with other number combinations.
A second group who have mastered this first grade skill will work with bundles of tens to make 100 (the second grade Common Core expectation). These students will use base 10 blocks for tens and hundreds. They will lay out the 100 block and then one ten. They will then add groups of ten until they have 100. How many bundles of ten did they need to add? (9 bundles) How much is 9 bundles of 10? (90). Students will continue to do number pairs of bundles of 10s that equal 100.
A group who is secure with bundles of tens for 100 could do bundles of 100 to make 1,000.
The groups will work for 15 minutes each and then work on their rhyme paper, or work on the rhyme paper first and then come to the table to do the activity.
It is important for students to come together at the end of the lesson to reinforce their learning of partners of ten and one hundred. I ask students to clean up their materials and return to their desks. I ask for students to tell me what a partner of ten is. I take several definitions from students. I repeat them so that everyone is hearing them.
Next I put the problem, "There were 8 snowflakes on my mitten. Now there are 10. How many more snowflakes did I catch?" I ask students to raise their hands if they know the answer and to show me with fingers. I ask children how many of them used a partner of ten to solve the problem?
Even though a child may copy peers in this show of hands activity, they are also noticing how many of their peers used partners of ten and this may be an incentive for them to try it next time. While I want to make sure some children are using the partners of ten, I also know that this is a beginning of using the partners of ten, and I want students to become familiar so I am not as concerned with children copying their peers on this process.