Lesson 15
Riddles (optional)
Lesson Purpose
Lesson Narrative
This lesson is optional because it does not address any new mathematical content standards. This lesson does provide students with an opportunity to apply precursor skills of mathematical modeling.
In previous lessons, students represented addition and subtraction on the number line and considered different methods based on the numbers being added and subtracted.
In this lesson, students apply previous understandings of the methods and representations for addition and subtraction problems within 100 to write and solve their own real-world problems. Students are encouraged to use the number line to represent the ages and solve problems. In the first activity, they become familiar with the context by solving problems about ages using any method that makes sense to them. In the second activity, they write their own problems about the ages of people they know, represent the problems, and solve them.
In this lesson, when students decide what quantities are important in a real-world situation, use these quantities to develop their own story problems, and choose math that matches a simplified situation, they build the precursor skills they need to model with mathematics (MP4).
- Representation
- MLR7
Learning Goals
Teacher Facing
- Solve addition and subtraction problems to investigate in context.
- Write addition and subtraction story problems.
Student Facing
- Let’s use what we know about adding and subtracting to solve and write riddles about people’s ages.
Required Materials
Materials to Copy
- Number Line to 100
Required Preparation
Warm-up:
- Create a number line from 0–100, marking intervals of 5, to display during the synthesis.
Lesson Timeline
Warm-up | 10 min |
Activity 1 | 15 min |
Activity 2 | 20 min |
Lesson Synthesis | 10 min |
Teacher Reflection Questions
Suggested Centers
- Jump the Line (2–5), Stage 1: Add and Subtract within 100 (Addressing)
- Number Line Scoot (2–3), Stage 1: Twos, Fives, and Tens (Addressing)
- How Close? (1–5), Stage 3: Add to 100 (Supporting)