Introduction to Multiplication

Objective

By the end of this 45-minute session, 1st grade students will:

• Understand multiplication as repeated addition using arrays and grouping methods.
• Represent simple multiplication problems using pictures and number sentences.
• Solve basic multiplication problems within 10.

Common Core Standards

• CCSS.MATH.CONTENT.1.OA.C.5: Understand and apply properties of operations and the relationship between addition and subtraction.
• CCSS.MATH.CONTENT.1.OA.C.6: Add and subtract within 20, demonstrating fluency for addition within 10. (Foundation for multiplication)
• CCSS.MATH.CONTENT.1.OA.A.1: Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions.
• Note: While multiplication is formally introduced generally starting in grade 3, this lesson carefully introduces the concept of multiplication as repeated addition to align with CCSS’s emphasis on understanding operations and relationships.

Materials

• Whiteboard and markers
• Grid paper or printed dot arrays (5x5 grids)
• Counters or small colored chips (around 60 total)
• Multiplication story cards (2-3 simple stories involving equal groups)
• Chart paper with multiplication vocabulary and picture examples
• Individual mini whiteboards with dry erase markers for each student

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Lesson Breakdown

1. Warm-Up Review (5 minutes)

Goal: Activate prior knowledge of addition and grouping.

• Ask students to think about how addition works as “putting groups together.”
• Write a simple addition problem like 3 + 3 + 3 on the board.
• Ask: “Can anyone tell me another way to say this?” Guide them toward understanding this as three groups of three.
• Show groups with counters: 3 counters in 3 piles.

2. Introduction to Multiplication Concept (10 minutes)

Goal: Introduce multiplication as repeated addition using Singapore Math's CPA (Concrete - Pictorial - Abstract) approach.

• Start with Concrete: Give each student 12 counters. Ask them to make equal groups (e.g., 3 groups of 4 counters).
• Pictorial: Draw simple arrays on the board (e.g., 3 rows with 4 dots in each). Show how this represents equal groups.
• Write the number sentence: "4 + 4 + 4 = 12" and introduce a multiplication sentence for the same: "3 × 4 = 12".
• Emphasize the 'times' sign means how many groups, and the second number means how many in each group.
• Show a real-world example: “If you have 3 baskets and each basket has 4 apples, how many apples do you have in total?”

3. Guided Practice with Story Cards (12 minutes)

Goal: Practice turning real-life equal group problems into multiplication sentences.

• Distribute simple story cards describing equal groups (e.g., “There are 5 boxes with 2 toys in each box.”).
• Students use counters to model the problem concretely.
• Then, draw pictorial arrays in their mini whiteboards.
• Finally, write the multiplication number sentence (e.g., 5 × 2 = 10).
• Monitor and assist students as needed. Encourage multiple students to share their answers to foster discussion.

4. Interactive Group Activity - Magic Array Challenge (10 minutes)

Goal: Reinforce multiplication as arrays in an engaging, game-like format.

• Split the class into pairs. Each pair receives a grid paper with dots and 20 counters.
• The challenge: “Make as many different arrays as you can using the counters on your grid paper.”
• For each array, write the multiplication sentence on their mini whiteboards.
• Example: 2 rows of 3 counters = 2 × 3 = 6.
• Rotate pairs to briefly share their favorite arrays and explain.

5. Closure and Assessment (8 minutes)

Goal: Formatively assess students’ understanding.

• Call on students one at a time to model a multiplication problem with counters and draw it on the board.
• Use a quick verbal quiz:
  • “If I have 4 groups of 2 pencils, how many pencils do I have?”
  • Ask students to write or say the number sentence.
• Exit ticket: Students draw one array with counters or dots and write a multiplication sentence under it on their mini whiteboards. Collect quickly.

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Differentiation

• For struggling learners: Use smaller numbers and more concrete objects; pair with a buddy for support.
• For advanced learners: Challenge them with larger numbers or have them write multiplication story problems for classmates to solve.

Reflection and Teacher Notes

• This lesson blends Singapore Math’s CPA model with Common Core standards emphasizing understanding of operations rather than rote memorization.
• The hands-on counters and visual arrays help develop conceptual understanding critical at this early grade level.
• Keep tone playful and encouraging; use real objects to build lasting math confidence.

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This detailed approach will “wow” teachers by integrating Best Practices, Common Core alignment, and engaging Singapore Math models tailored thoughtfully for first graders starting to explore multiplication!