Students will be able to solve subtraction problems using numbers 0-10.
- Gather students together for the lesson and introduce the topic using the read-aloud text, Ten Red ApplesBy Pat Hutchins.
- As you read, emphasize the subtracting or removal of each apple from the tree.
- Conclude the read aloud by saying, "Today we are going to learn even more about subtracting or taking something away from something else!"
Explicit Instruction/Teacher modeling(5 minutes)
- Use your document camera to project the number cards and explain that you will be playing a game to practise taking away or SubtractingOne number or amount from another number.
- Demonstrate how to play the game by placing the two card decks face down in a pile in front of you and picking one card from the top of the 5–9 deck and saying the number aloud, e.g., "I picked a 5."
- Model how to count the same number of maths manipulatives as the number on the card, e.g., "I drew the 5 card from the deck, so now I am going to count out 5 cubes, 1---2---3--4---5. Now I am going to pull a card from the 0–4 deck, here is a 2 card. I am going to SubtractOr take away two cubes." As you model, use a think aloud strategy to share your process with the class, e.g., "How many cubes do I have left? I will count them, 1--2--3. That means 5 cubes minus 2 cubes equals 3 cubes."
- Write up the matching equation, 5 – 2 = 3, on the board and demonstrate how to read the equation to the class.
Guided practise(10 minutes)
- Explain that now you will get a chance to play the same game as a group.
- Draw a card from the 5–9 deck, hold it up and encourage the class to say the number aloud. Then invite the students to count chorally (or echo as needed) as you count out the matching number of manipulatives. Repeat with the second card as you model finding the DifferenceOf the two cards.
- Model how to use the cards to write a matching subtraction equation on the board and have students echo read the equation after you.
- Explain that now students will get to play the game with a partner. Demonstrate how each student will get their own deck (0–4 or 5–9) with the first student (Partner A) choosing the first card from the 5–9 deck and counting out the first set of manipulatives. Then the second student (Partner B) will choose the second card from the 0–4 deck and will subtract the matching number of manipulatives. Both partners will then work together to find the difference or remainder left.
Independent working time(15 minutes)
- Display the Take Away the Bugs worksheet and tell the students that now they will get to practise solving some subtraction problems on their own using pictures and maths manipulatives.
- Demonstrate how to read the equation and cross out the bugs to subtract.
- Pass out worksheets, maths counters, and pencils to each student.
- At the start of the lesson or in a pre-lesson, review the numbers 0–10 using songs, games, flashcards, or art activities.
- Pass out a number line and/or hundreds charts for students to use during the independent work portion of the lesson.
- Teach and focus on one strategy for students to use when solving subtraction equations (e.g., crossing out the number to be subtracted, or moving manipulatives to a separate pile).
- Practise reading and writing subtraction equations in the standard format (7 - 3 = 4) and have students practise solving these equations using numbers instead of visuals.
- Write additional equations using numbers 11–20 for students to solve.
- Encourage students to solve problems using a variety of self chosen strategies (e.g., number line, maths counters, pictures, etc.) and to explain how and when to choose each strategy.
- Use guiding questions to assess student understanding of the objective. Questions could include, "What is the number on your card? How do you know? How many maths counters are you placing under the card? How do you know it is ____ number? How many are there in all? How do you know?"
- Check for any areas of confusion or misunderstanding (e.g., counting the same object more than once, skipping objects when counting, adding instead of subtracting, etc.).
- Collect student work samples and check for accuracy.
Review and closing(5 minutes)
- Gather the class back together to play an interactive version of Choose It Subtraction. Choose a number card from the 5–9 deck and invite that number of students to the front of the room. Have the rest of the class count the students chorally as you point to each one. Draw a card from the 0–4 deck and subtract or remove that many students. Encourage the class to count with you to find the total number of students left. Write up the equation on the board to match the cards drawn.
- Close by having students turn and talk to a partner to share something they enjoyed about today's maths lesson.