Round Decimals

Grade 5 · decimals · 82 practice problems · read aloud

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Rounding Decimals

What is Rounding and Why is it Useful? 🤔

Rounding means making a number simpler or "rounder" but keeping its value close to what it was. We round decimals to make them easier to work with, estimate answers, or report measurements. For example, if a race is 10.27 seconds long, we might say it's about 10.3 seconds.

How to Round Decimals: Step-by-Step

  1. Step 1: Identify the place value you are rounding to (e.g., tenths, hundredths). Circle it!
  2. Step 2: Look at the digit to the immediate right of your circled number. This is your "decider."
  3. Step 3: Apply the rule:
    • If the "decider" is 4 or less (0, 1, 2, 3, 4), the circled digit stays the same.
    • If the "decider" is 5 or more (5, 6, 7, 8, 9), the circled digit rounds up by 1.
  4. Step 4: Drop all digits to the right of the place you're rounding to.

Visual Examples

Example 1: Round 3.47 to the nearest tenth.

  1. We are rounding to the tenths place. Circle the 4: 3.47
  2. The "decider" to the right is 7.
  3. 7 is 5 or more, so the 4 rounds up to 5.
  4. Drop the 7. Answer: 3.5

Example 2: Round 2.153 to the nearest hundredth.

  1. We are rounding to the hundredths place. Circle the 5: 2.153
  2. The "decider" to the right is 3.
  3. 3 is 4 or less, so the 5 stays the same.
  4. Drop the 3. Answer: 2.15

Common Mistakes to Avoid

⚠️ Rounding the Wrong Digit: Always make sure you know which place value you are rounding TO before you start. Underline or circle it!

⚠️ Forgetting to Drop Digits: After you round, you must drop all the digits to the right. Rounding 8.79 to the nearest tenth is 8.8, not 8.80.

⚠️ Confusing the Rule: Remember: 4 or less, the digit rests. 5 or more, give it a shove (up)!

Tips & Tricks

🎯 The Roller Coaster Method: Draw a hill. Put numbers 0-4 on the left side (they roll back down and stay the same). Put numbers 5-9 on the right side (they roll over the hill and push the number up)!

🎯 Rhyme Time: "Four and below, let it go. Five and above, give it a shove."

🎯 Place Value is Key: Always write your place value chart: Hundreds | Tens | Ones | . | Tenths | Hundredths | Thousandths

How to Practice

  • Flashcards: Create cards with a decimal on one side and the rounded answer on the back.
  • Real-World Problems: Round prices at the store, sports statistics, or measurements in recipes.
  • Online Games: Find interactive math games focused on rounding decimals for quick, fun practice.
  • Worksheet Drills: Practice with mixed problems, rounding to the tenths, hundredths, and even whole numbers!

Practice problems

6 of the 82, worked through step by step — try them before opening the answer.

1 round(3.785, 2) = ?

Hint: When rounding to two decimal places, look at the third decimal digit to decide whether to round up or keep the same.

Show the answer

Answer: 3.79

  1. Identify the digit in the hundredths place (second decimal place): 8
  2. Look at the digit in the thousandths place (third decimal place): 5
  3. Since the thousandths digit is 5 or greater, we round up the hundredths digit from 8 to 9
  4. The rounded number becomes 3.79
  5. Verify: 3.785 rounded to two decimal places is 3.79

2 round(9.847, 1) = ?

Hint: Look at the digit in the tenths place and then check the digit in the hundredths place to decide whether to round up or keep the same.

Show the answer

Answer: 9.8

  1. Identify the digit in the tenths place (first decimal place): 8
  2. Look at the digit in the hundredths place (second decimal place): 4
  3. Since the hundredths digit is 4, which is less than 5, we do not round up.
  4. The tenths digit (8) stays the same, and we drop all digits to the right.
  5. The rounded number is 9.8.

The answer is 9.8.

3 Round 8.475 to the nearest tenth.

Hint: Look at the digit in the hundredths place to decide whether to round the tenths place up or keep it the same.

Show the answer

Answer: 8.5

  1. Identify the digit in the tenths place. In 8.475, the tenths digit is 4.
  2. Look at the digit to the right (the hundredths place), which is 7.
  3. Since the hundredths digit (7) is 5 or greater, we round the tenths digit (4) up by 1, making it 5.
  4. The digits after the tenths place become zero, so 8.475 rounded to the nearest tenth is 8.5.

4 Round 6.384 to the nearest tenth.

Hint: Look at the digit in the hundredths place to determine whether to round the tenths place up or keep it the same.

Show the answer

Answer: 6.4

  1. Identify the digit in the tenths place. In 6.384, the digit in the tenths place is 3.
  2. Look at the digit immediately to the right, which is the hundredths place. The digit in the hundredths place is 8.
  3. Since the hundredths digit (8) is 5 or greater, we round the tenths digit (3) up by 1. 3 becomes 4.
  4. The digits to the right of the tenths place become zero, so 6.384 becomes 6.400.
  5. We can drop the trailing zeros after the tenths place, so the final answer is 6.4.

5 Round 8.357 to the nearest tenth.

Hint: Look at the digit immediately to the right of the tenths place to determine whether to round up or keep the same.

Show the answer

Answer: 8.4

  1. Identify the digit in the tenths place: 8.3 (the 3 is in the tenths place)
  2. Look at the digit to the right (the hundredths place): It is 5
  3. Since the digit is 5 or greater, we round the tenths place up from 3 to 4
  4. All digits to the right of the tenths place become zero: 8.400
  5. Remove unnecessary zeros after the decimal: 8.4

The answer is 8.4.

6 Round 9.847 to the nearest tenth.

Hint: Look at the digit in the hundredths place to decide whether to round the tenths digit up or keep it the same.

Show the answer

Answer: 9.8

  1. Identify the digit in the tenths place (first digit after the decimal): 8.
  2. Look at the digit in the hundredths place (second digit after the decimal): 4.
  3. Since 4 is less than 5, we do not round up the tenths digit. The 8 stays the same.
  4. Drop all digits to the right of the tenths place.
  5. The rounded number is 9.8.

The answer is 9.8.

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