# Lesson 15

Round to the Nearest Ten and Hundred

### Lesson Purpose

The purpose of this lesson is for students to round whole numbers within 1,000 to the nearest ten or hundred.

### Lesson Narrative

Before this lesson, students named multiples of 10 and 100 that are near given numbers and identified the multiple of 10 or 100 that was closest. They located numbers on a number line and approximated their distance from adjacent tick marks that indicate tens, or from endpoints that mark hundreds.

Here, students learn that sometimes, when we round to the nearest ten and the nearest hundred, we round to the same number. Students also learn that when numbers are right in the middle of two multiples of 10 or 100, the convention is to round up. Students use rounding to estimate the number of students in a school and see that rounding to the nearest ten and the nearest hundred can give different estimates for the same situation.

• Representation
• MLR1

### Learning Goals

Teacher Facing

• Round whole numbers within 1,000 to the nearest ten and hundred, using the convention of rounding up when the number is halfway between two multiples of 10 or 100.

### Student Facing

• Let’s round to the nearest ten and hundred.

Building On

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

How is your students’ understanding of place value contributing to their work rounding to the nearest ten and hundred?

### Suggested Centers

• Target Numbers (1–5), Stage 7: Subtract Hundreds, Tens, or Ones (Addressing)