Find a Match!
Lesson 5 of 8
Objective: SWBAT match number sentences that are equal. SWBAT combine 2 addends that equal 10 to help them solve a 3 addend number sentence.
Hook and Objective
I will use the Matching Pairs for 10 Game from Dreambox Learning. You can get to the game by scrolling down to the Kinder Addition and Subtraction section. It is a free tool that I project onto the promethean board. I will show the game board, and students will get a whiteboard. They will record as many number sentences as they can that equal 10. They only get 4 minutes to record. After they record the number sentences, I'll have students "popcorn" call our the pairs. If we have time, we will play a game with a new gameboard.
This game pushes math fact fluency to 10, an explicit part of 1.OA.C6. This key common core shift insures that students build number fluency gradually from Kindergarten on! Students with solid fluency can use their number facts to help them solve more difficult problems. For example, if you understand that 8+2 is 10, you can apply that to help you solve 8+3 (8+2 and 1 more) and even 18 +2 (1 ten, 8 ones and 2 ones).
Review and Connect:
We have been solving story problems and showing lots of strategies to do so all year. Today we are going to look closely at another strategy-we are going to see if we can use 10, our best number friend, to help make solving story problems easier.
Your thinking job today is: Where is 10 in this number sentence?
Present problem: I own a pet store. There are 9 dogs, 1 cat and 3 fish in the store. How many pets are in the store?
Guiding Questions to do in partners:
- Retell the story problem.
- What number sentence could you write to match this story problem?
- Where is 10 in this number sentence?
I will circle the two numbers that equal 10 and "Make a Bunny" to show how we made the 10.
Partner talk: What new number sentence could we write to match what we did? I want students to show that 9 + 1 + 3 could be written as 10 +3 because we used 10 to solve.
Restate: We can write 9 + 1 + 3 to match the problem, but we made 10! The number sentence we could write to show how we solved is 10 + 3.
I will use white boards during this part of the lesson to encourage active engagement from all students. This strategy also allows you as the teacher to quickly identify misconceptions and address them with students.
I will present a number sentence to students and tell them to identify the ten. Then students will write the new number sentence that includes 10!
Present problem: 8 + 2 + 4
- Students "make a bunny" with the addends that make 10.
- Students figure out the total.
- Students write a number sentence with 10 to show how to solve. (10+4)
Partner talk: Where did the 8 and 2 go? Why is the 4 still there?
Other problems: 5 + 5 + 2; 6 + 4 + 3; 1 + 9 + 6
Directions: Students take their number cards and cut them out. They they solve the number facts and quickly show how they did it on the number card. Then students glue the number cards in groups of 3 on their construction paper hot dog folds (see example of fold here).
Right on Track: Most students will use the make 10 cards in the first set. See this video for how one student used making 10 to help her solve 5 + 5 + 3. I also ask her a lot of questions to ensure that she truly understands WHY she could make 10 and WHY she still had to add 3.
Intervention: For students who struggle with mental math, they might just need a reduced number of cards and cubes to represent.
Extension: Students who have already mastered making 10 mentally to help them solve need an extension! I am working with these students on learning the number pairs for 50. This will help them learn to use 50 as a helpful number like they are already using 10!
See this video example of one student's work and how she used 50 to help her solve the problems. You'll also hear the questioning I use to help make sure she fully understands each strategy.
All cards for independent practice are attached: Equality Sorts_Make 10_Make 50.docx
Students share one of their number fact folds with a partner. Each student is expected to prove that those 3 number facts are equal. This emphasis on "proving it" is aligned to MP3, Construct viable arguments and critique the reasoning of others. Constant practice explaining student thinking helps students work towards this mathematical practice!