# Lesson 23

Bees are Buzzing (optional)

### Lesson Purpose

The purpose of this lesson is to use estimation to make sense of a wide range of numbers and to use addition and subtraction to investigate how an insect population can change over time.

### 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 developed place value understanding for numbers up to 1,000,000 and rounded, added, and subtracted numbers in this range. In this lesson, they apply their understandings and skills to make sense of facts about insects and investigate how an insect population changes over time.

Students make decisions and choices, adhere to mathematical constraints, use mathematical ideas to analyze real-world situations, and interpret a mathematical answer and whether it makes sense in the context of a situation. In doing so, they model with mathematics (MP4).

• Representation
• MLR5

### Learning Goals

Teacher Facing

• Add and subtract multi-digit whole numbers using the standard algorithm.
• Use place value understanding to make reasonable estimates.

### Student Facing

• Let’s investigate insect populations.

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Lesson Synthesis 10 min

### Teacher Reflection Questions

As students worked together today, where did you see evidence of a mathematical community?