Rounding Decimals: Get Close to the Value!

Mathematics Grades 5th Grade 6:28 Video
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Lesson Description

Learn how to round decimals to the nearest tenth, hundredth, and thousandth place. This lesson uses examples and easy-to-follow steps to help you master rounding decimals!

Video Resource

How to Round Decimals | Math with Mr. J

Math with Mr. J

Duration: 6:28
Watch on YouTube

Key Concepts

  • Place Value (Tenths, Hundredths, Thousandths)
  • Rounding Rules (5 or more, round up; 4 or less, stay the same)
  • Approximation

Learning Objectives

  • Students will be able to identify the place value to which they are rounding.
  • Students will be able to apply the rounding rules to round decimals to the nearest tenth, hundredth, and thousandth.
  • Students will be able to explain why rounding is useful in real-world situations.

Educator Instructions

  • Introduction (5 mins)
    Begin by explaining why rounding is important in everyday life. Ask students for examples where they might use rounding (e.g., estimating costs, measuring ingredients). Briefly introduce the concept of finding a close or approximate value.
  • Video Viewing (10 mins)
    Play the YouTube video "How to Round Decimals | Math with Mr. J". Instruct students to take notes on the steps Mr. J uses to round decimals. Emphasize the importance of identifying the place value and the digit to the right.
  • Guided Practice (15 mins)
    Work through several examples of rounding decimals on the board. Start with rounding to the tenths place, then move to hundredths and thousandths. For each example, have students identify the place value to be rounded, the digit to the right, and whether to round up or stay the same. Use the '5 or more raise the score, 4 or less let it rest' saying.
  • Independent Practice (15 mins)
    Provide students with a worksheet containing various decimal numbers to round to different place values. Have them work independently to apply the rounding rules. Circulate to provide assistance and answer questions.
  • Review and Wrap-up (5 mins)
    Review the answers to the independent practice worksheet. Ask students to share any challenges they faced and how they overcame them. Reiterate the key concepts and the importance of rounding.

Interactive Exercises

  • Number Line Rounding
    Draw a number line on the board. Place a decimal number on the number line and ask students to identify the nearest whole number, tenth, or hundredth, depending on what you want them to round to. This helps visualize the concept of approximation.
  • Real-World Rounding
    Present students with real-world scenarios involving decimals (e.g., prices of items, measurements of objects). Ask them to round the decimals to a specified place value to make estimations or comparisons.

Discussion Questions

  • Why is rounding helpful in everyday situations?
  • How does place value help you when rounding decimals?
  • What happens if the digit to the right of the place you're rounding to is a 5?

Skills Developed

  • Place Value Understanding
  • Decimal Comparison
  • Problem-Solving
  • Estimation

Multiple Choice Questions

Question 1:

What place value is the 8 in the number 3.182?

Correct Answer: Hundredths

Question 2:

Which of these numbers will round UP to the nearest tenth?

Correct Answer: 4.25

Question 3:

Round 7.63 to the nearest tenth.

Correct Answer: 7.6

Question 4:

Round 12.485 to the nearest hundredth.

Correct Answer: 12.49

Question 5:

Which digit do you look at to determine if you round up or stay the same?

Correct Answer: The digit to the right

Question 6:

What does it mean to round a number?

Correct Answer: To find a close or approximate value

Question 7:

What is 3.14159 rounded to the nearest hundredth?

Correct Answer: 3.14

Question 8:

What is 9.99 rounded to the nearest tenth?

Correct Answer: 10.0

Question 9:

If you are rounding to the nearest whole number, what place value do you look at?

Correct Answer: Tenths

Question 10:

What rule helps you remember whether to round up or down?

Correct Answer: 5 or more raise the score, 4 or less let it rest

Fill in the Blank Questions

Question 1:

When we round, we find a ________ or approximate value.

Correct Answer: close

Question 2:

If the digit to the right is 5 or _______, we round up.

Correct Answer: more

Question 3:

If the digit to the right is 4 or _______, we stay the same.

Correct Answer: less

Question 4:

When rounding, it's important to identify the _________ _________ we are rounding to.

Correct Answer: place value

Question 5:

Rounding helps us make numbers easier and _________ to work with.

Correct Answer: simpler

Question 6:

3. 45 rounded to the nearest tenth is _________.

Correct Answer: 3.5

Question 7:

The hundredths place is two places to the _______ of the decimal point.

Correct Answer: right

Question 8:

The tenths place is one place to the _______ of the decimal point.

Correct Answer: right

Question 9:

If rounding 2.5 to the nearest whole number, the answer would be _________.

Correct Answer: 3

Question 10:

___________ to the right of a decimal do not change the value of that decimal, so they can be left off when rounding.

Correct Answer: zeros

Educational Standards

5.N.1.2:Read, write, and represent decimals using place value to describe decimal numbers including fractional numbers as small as thousandths and whole numbers up to seven digits. 5.N.1.3:Compare and order decimals and fractions, including mixed numbers and fractions less than one, and locate on a number line. 5.N.3.1:Estimate sums and differences of fractions with like and unlike denominators, mixed numbers, and decimals to assess the reasonableness of the results.

Teaching Materials

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