# Lesson 15 Round to the Nearest Ten and Hundred

Let’s round to the nearest ten and hundred.

## Warm-up Choral Count: Tens and Hundreds

Count by 10, starting at 0.

What patterns do you see?

## Activity 1 Can the Nearest Ten and Hundred be the Same?

Round each number to the nearest ten and the nearest hundred. Use number lines if you find them helpful.

number

nearest ten

nearest hundred

Kiran and Priya are rounding some numbers and are stuck when trying to round 415 and 750.

Kiran said, “415 doesn’t have a nearest multiple of 10, so it can’t be rounded to the nearest ten.”

Priya said, “750 doesn’t have a nearest multiple of 100, so it can’t be rounded to the nearest hundred.”

Do you agree with Kiran and Priya? Explain your reasoning.

## Activity 2 Round to Estimate

The table shows the numbers of people in different parts of a school at noon during a school day.

Andre and Lin are trying to estimate the number of people in the whole school. Andre plans to round the numbers to the nearest hundred. Lin plans to round them to the nearest ten.

Make a prediction: Whose estimate is going to be greater? Explain your reasoning.

Work with a partner to find Andre and Lin’s estimates. Record them in the table.

location

number

Andre’s estimate (nearest hundred)

Lin’s estimate (nearest ten)

playground

cafeteria

art room

library

classrooms

gymnasium

music room

total

Make two observations about the completed table. Was your prediction correct?

## Practice Problems

## Problem 1

What is 346 rounded to the nearest ten? Explain or show your reasoning.

What is 346 rounded to the nearest hundred? Explain or show your reasoning.

## Problem 2

Round each number to the nearest ten and to the nearest hundred. Explain or show your reasoning.

254

145