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Adding Three is a Breeze!
Students will be able to add three numbers using objects from a word problem.
- Call students together as a group. Explain that today they will work on adding three numbers.
- Review with students that when we add, we put two numbers together to find out the combined total value.
- Briefly review adding 7+6 and 11+5. Review with students the terms Sum, or the answer to the addition problem, and Addend, or one of the components that is added.
- Tell students that when we add three numbers we follow the same process as adding two numbers to get a sum.
- Tell students that today we will practise reading some number stories with three whole numbers.
Explicit Instruction/Teacher modeling(15 minutes)
- Read this problem from the board: “Lily saw 2 rabbits, 5 birds, and 4 dogs at the park today. How many animals did she see in all?”
- Think aloud to model solving this problem. Tell students that in this problem, we can see that Lily saw many animals. We know that she saw 2 rabbits, 5 birds, and 4 dogs at the park.
- Tell students that because the problem is asking for the total number of animals Lily saw, we have to use addition.
- Show students how to use counters to solve the problem.
- Model picking one colour of counter to represent each animal.
- Model counting each counter. Move each counter over as your count. Emphasize that it is important to make sure to count each counter one by one. It is helpful to touch each counter so that one counter does not get counted twice or missed.
- Once you have counted to eleven, tell your students that you know this means Lily saw 11 animals, as each counter represents one animal.
- Repeat this model two more times. Make up two word problems using students’ names and objects in the classroom.
Guided practise(15 minutes)
- Give each pair of students a set of counters and whiteboard and marker or paper.
- Continue using students’ names and objects from the classroom to create word problems that fit your model.
- After reading each problem, have students work with a partner to arrange the counters to represent each problem.
- Have students write the number sentence on the whiteboard. Have students work together to accurately find the sum.
- Do this with at least 4 sets of problems. Circulate as students work together.
Independent working time(15 minutes)
- Give each student a copy of the Three Pigs Addition worksheet.
- Encourage students to continue using the counters for support.
- Tell students to copy their number sentence onto the worksheet to show their thinking.
- Continue to circulate to offer support and guidance.
- Enrichment:For students in need of a greater challenge, you may change the addends to be a greater number or introduce a fourth addend to a problem to increase the difficultly.
- Support:For students in need of extra support, consider using paper cups and a box to organise the counters. Have the student place each set of counters in the problem into a cup. When finding the sum, pour the contents of all three cups into a box and have the student count how many are there altogether.
- To assess students' understanding during the lesson, circulate while students are working.
- During the guided practise portion, on your cue, have the students lift their whiteboards to show their number sentence. This will give you immediate feedback to determine which pairs may need extra support.
- Collect the Three Pigs Addition worksheet to further assess individual learning.
Review and closing(10 minutes)
- Call students together as a group. Ask students to share about their experience using the counters as a strategy to solve the problems. What did the counter represent? How did they know to count them altogether? How could they use this strategy at home? How did the counters help them write the addition sentence for the problem?
- Remind students that adding three whole numbers is just like adding two whole numbers. Encourage them to practise with sets at home.