Exploring the Marvelous Number 19!

Materials Needed

• Paper and drawing supplies (crayons, markers)
• A large collection of small counting objects (up to 25 items): dry beans, small blocks, buttons, or pennies
• Two different colors of objects (e.g., 10 blue blocks, 9 red blocks)
• A ruler or tape measure (optional, for measuring 19 units)
• A pre-drawn number line going from 10 to 25

Introduction (10 minutes)

Hook: The Almost-Twenty Number

Teacher/Facilitator Talking Points: "If you had 20 super cool toys, but lost just one, how many would you have left? You would have 19! Nineteen is a very important number because it is the biggest number we write before we start counting in the 'twenties.' Today, we are going to become experts on the amazing number 19!"

Learning Objectives (Success Criteria)

By the end of this lesson, you will be able to:

1. Locate the number 19 on a number line and explain what numbers come before and after it.
2. Model the number 19 using place value (tens and ones).
3. Find at least three different ways to make the number 19 using addition.
4. Successfully count and display a group of 19 items.

Body: Exploring the Structure of 19

Phase 1: I Do (Modeling Place Value) (15 minutes)

Activity: Ten and Nine More

Success Criteria Check: Can the learner identify the 'ten' group and the 'ones' group?

1. Modeling Place Value: Gather your counting objects. Use the two different colors (e.g., blue for the 'tens' and red for the 'ones').
2. Teacher Demonstration: "The number 19 has two digits: a '1' and a '9'. The '1' is in the tens place, and the '9' is in the ones place."
3. Physical Model: Place 10 blue objects together in a neat stack or row (the 'Ten Group'). Say: "This is 1 group of ten."
4. Adding the Ones: Place 9 red objects next to the ten group. Count them aloud (1, 2, 3... 9). Say: "These are the 9 extra ones."
5. Combining: Point to the stack of 10 and count on the extra 9: "10... 11, 12, 13, 14, 15, 16, 17, 18, 19! See? 19 is just one whole ten and nine ones."

Phase 2: We Do (Guided Practice with Addition) (20 minutes)

Activity: How Can We Make 19? (Fact Families)

Success Criteria Check: Can the learner find two different number combinations that equal 19?

1. Number Line Jump: Use the number line (10 to 25). Start at 10. Ask the learner to count how many jumps they need to get to 19. (9 jumps). Write the equation: 10 + 9 = 19.
2. Doubles Strategy: Discuss a known math fact, like 9 + 9 = 18. Ask: "If 9 plus 9 equals 18, how much more do we need to reach 19?" (One more). Write the equation: 9 + 9 + 1 = 19. (Alternatively, 8 + 11 = 19).
3. Think-Pair-Sketch (Visualizing 19): Challenge the learner to use their paper and markers to draw 19 things, but separate them into two groups.
   • Example 1 (Facilitator Model): Draw 14 stars on the left and 5 moons on the right. Write the equation: 14 + 5 = 19.
   • Learner Practice: Have the learner choose their own two groups (e.g., red apples and green apples) and draw them, then write the corresponding equation. (Formative Assessment: Observe their counting accuracy and partitioning strategy.)

Phase 3: You Do (Independent Application) (25 minutes)

Activity: The Great 19 Collection Challenge

Success Criteria Check: The learner accurately counts out a specific set of 19 items and presents it.

1. The Mission: Tell the learner they are now a "Curator of 19" and must find or create a collection of exactly 19 items.
2. Choice & Autonomy: Provide options for the collection (choose one):
   • Find 19 specific objects around the room (e.g., 19 pencils, 19 small toys).
   • Draw a picture that clearly shows 19 items (e.g., 19 dots, 19 people).
   • Make a chain using 19 paperclips or links (if materials are available).
3. Counting Strategy (Real-World Relevance): Require the learner to count their collection out loud, grouping them into sets of five or ten to ensure accuracy. (e.g., "Here is my group of 10 blocks, and here are the 9 extras.")
4. Presentation: Have the learner present their 19 collection and explain their counting strategy.

Conclusion (10 minutes)

Recap and Reflection

Teacher/Facilitator Talking Points: "Wow, you found 19 things! That means you know exactly where 19 lives in the number world."

1. Quick Fire Review:
   • What number comes right after 19? (20)
   • What number is ten less than 19? (9)
   • How many 'tens' are in 19? (One ten)
2. Exit Ticket (Summative Assessment): On a small piece of paper, ask the learner to write the number 19 and draw 19 tally marks next to it. (Five lines with a slash across, repeated three times, plus four more: III I/ IIII I/ IIII I/ IIII)

Differentiation and Extension

Scaffolding (For learners needing extra support)

• Use a physical hundreds chart and have the learner locate 19, physically covering all numbers up to 18 to isolate 19.
• Pre-draw the addition circles for the "We Do" activity, requiring them only to fill in the numbers.
• Focus only on the 10 + 9 structure, reinforcing that one ten is the key.

Extension (For advanced learners)

• Subtraction Challenge: Ask them to find two subtraction problems that result in 19 (e.g., 25 - 6 = 19; 30 - 11 = 19).
• Grouping: Challenge them to see if 19 can be divided evenly into equal groups (discover it is a prime number, although they don't need the term, just the concept).
• Money Math: How many dimes and pennies would you need to make 19 cents? (1 dime and 9 pennies).