NVACS: Number Base Ten (4.NBT.3)

Name: ______Date: ______

NVACS: Number Base Ten (4.NBT.3)

Place Value, Rounding

Practice For 4th Graders

The expectation is that students have a deep understanding of place value and number sense and can explain and reason about the answers they get when they round. Students should have numerous experiences using a number line and a hundreds chart as tools to support their work with rounding. This standard refers to place value understanding, which extends beyond an algorithm or procedure for rounding.

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Example

Your class is collecting bottled water for a service project. The goal is to collect 300 bottles of water. On the first day, Max brings in 3 packs with 6 bottles in each container. Sarah wheels in 6 packs with 6 bottles in each

container. About how many bottles of water still need to be collected?

Student 1

First, I multiplied 3 and 6 which equals 18. Then I multiplied 6 and 6 which is

36. I know 18 plus 36 is about 50. I’m trying to get to 300. 50 plus another 50

is 100. Then I need 2 more hundreds. So we still need 250 bottles.

Student 2

First, I multiplied 3 and 6 which equals 18. Then I multiplied 6 and 6 which is 36. I know 18 is about 20 and 36 is about 40. 40+20=60. 300 60 = 240, so we need about 240 more bottles.

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Example of a number line as a tool for rounding. 368 can be rounded to 350.

If a number was rounded to 300, what could the number have been originally?

If a number was rounded to 500, what would have been the lowest and highest values for the number if the number was rounded to the tens? What would have been the lowest and highest values of the number if the number was rounded to hundreds? Explain your thinking.

What are two different numbers you could round 4,596 to? Explain your thinking.

Why is rounding important?

When might it be valuable to round to the hundreds place, and when might it be valuable to round to the tens place? For example, when ordering new pencils, round up to 400 because it’s okay to have a lot extra and they will get used, but if ordering bagged lunches for a field trip round to 380 because you wouldn’t want the food to go to waste.

When might you use rounding when adding and subtracting numbers? How about when working with fractions?

Place 1,525 on the number line below.

1,000 2,000

Use the number line above as a tool to help you round the numbers in the problem.

Round 1, 535 to the nearest thousand. ______

Round 1, 875 to the nearest thousand. ______

Round 1, 499 to the nearest thousand. ______

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When rounded to the nearest thousand, an elephant’s weight is 5,000 pounds. What is the least amount that the elephant could weigh? Use pictures, numbers, and words to represent your thinking.

Emily said, “When I round all of these numbers, I get the same answer.”

Tiffany said, “I disagree. I get all different numbers.”

Can they both be correct? Explain your reasoning.

A number has been rounded to 700. What might the number be?

Give three possible answers.

______was rounded to the nearest ______

______was rounded to the nearest ______

______was rounded to the nearest ______

Find two numbers that may be rounded and added together to make 50.

Demonstrate your reasoning below.

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