Round Decimals

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Round Decimals · Grade 4 · Worksheet 1

1. Sophia is training for a 5-kilometer fun run. On Monday, she ran 3.7 kilometers. On Tuesday, she ran 4.2 kilometers. Sophia wants to know her total distance for both days rounded to the nearest whole kilometer. What is the total distance rounded to the nearest whole kilometer? Answer: 8 Solution: Add the distances: 3.7 + 4.2 = 7.9 kilometers. To round 7.9 to the nearest whole number, look at the tenths digit. The tenths digit is 9.
   Full step-by-step solution

   Step 1: Add the distances: 3.7 + 4.2 = 7.9 kilometers. Step 2: To round 7.9 to the nearest whole number, look at the tenths digit. The tenths digit is 9. Step 3: Since 9 is greater than or equal to 5, we round up the whole number from 7 to 8. Step 4: The rounded total distance is 8 kilometers. Answer: 8

2. Emma is drawing a large number line on the playground. She marks a point at 15.8 meters. Then she draws another point at 20.5 meters. What is the distance between the two points on the number line, rounded to the nearest whole number? Answer: 5 Solution: Find the difference between the two points: 20.5 - 15.8 = 4.7 Round 4.7 to the nearest whole number. Look at the tenths digit: 7 is 5 or more, so we round up. 4.7 rounded to the nearest whole number is 5.
   Full step-by-step solution

   Step 1: Find the difference between the two points: 20.5 - 15.8 = 4.7 Step 2: Round 4.7 to the nearest whole number. Look at the tenths digit: 7 is 5 or more, so we round up. Step 3: 4.7 rounded to the nearest whole number is 5. The answer is 5.

3. Emma is baking cookies for her class party. The recipe calls for 1.25 cups of chocolate chips and 0.75 cups of peanut butter chips. How many total cups of chips does Emma need for the recipe? Answer: 2 Solution: Identify the amounts to add: 1.25 cups of chocolate chips and 0.75 cups of peanut butter chips. Write the addition problem: 1.25 + 0.75 Add the hundredths place: 5 + 5 = 10.
   Full step-by-step solution

   Step 1: Identify the amounts to add: 1.25 cups of chocolate chips and 0.75 cups of peanut butter chips. Step 2: Write the addition problem: 1.25 + 0.75 Step 3: Add the hundredths place: 5 + 5 = 10. Write 0 in the hundredths place and carry over 1 to the tenths place. Step 4: Add the tenths place: 2 + 7 + 1 (carried over) = 10. Write 0 in the tenths place and carry over 1 to the ones place. Step 5: Add the ones place: 1 + 0 + 1 (carried over) = 2. Step 6: The total is 2.00 cups, which is 2 cups. Emma needs 2 total cups of chips.

4. Round 125.8 to the nearest whole number = ? Answer: 126 Solution: Identify the digit in the ones (whole number) place: 125.8 has 5 in the ones place. Look at the digit in the tenths place: 125.8 has 8 in the tenths place. Since 8 is 5 or greater, we round the ones digit up from 5 to 6.
   Full step-by-step solution

   Step 1: Identify the digit in the ones (whole number) place: 125.8 has 5 in the ones place. Step 2: Look at the digit in the tenths place: 125.8 has 8 in the tenths place. Step 3: Since 8 is 5 or greater, we round the ones digit up from 5 to 6. Step 4: The number 125.8 rounded to the nearest whole number is 126. The answer is 126.

5. Round 5.678 to the nearest hundredth = ? Answer: 5.68 Solution: Identify the hundredths place: 5.678 (the 7 is in the hundredths place) Look at the digit to the right (thousandths place): 8 Since 8 is 5 or greater, round the hundredths place up from 7 to 8 5.678 rounded to the nearest hundredth is 5.68
   Full step-by-step solution

   Step 1: Identify the hundredths place: 5.678 (the 7 is in the hundredths place) Step 2: Look at the digit to the right (thousandths place): 8 Step 3: Since 8 is 5 or greater, round the hundredths place up from 7 to 8 Step 4: Drop all digits after the hundredths place Step 5: 5.678 rounded to the nearest hundredth is 5.68

6. Aroha is measuring the height of a plant in her garden. On Monday, the plant is 7.83 centimeters tall. On Friday, it has grown to 9.17 centimeters. What is the height of the plant on Friday rounded to the nearest whole centimeter? Answer: 9 Solution: The height on Friday is 9.17 centimeters. We need to round this to the nearest whole number. Step 2: Look at the digit in the tenths place, which is 1.
   Full step-by-step solution

   Step 1: The height on Friday is 9.17 centimeters. We need to round this to the nearest whole number. Step 2: Look at the digit in the tenths place, which is 1. Step 3: Since 1 is less than 5, we round down, meaning the whole number stays the same. Step 4: So 9.17 rounded to the nearest whole number is 9. The answer is 9.

7. Liam is measuring ribbon for a school project. He needs 3.75 meters of blue ribbon and 2.25 meters of red ribbon. If the ribbon is sold by the meter, how many total meters of ribbon should Liam buy to have enough for his project? Answer: 6 Solution: - Blue ribbon: 3.75 meters - Red ribbon: 2.25 meters Ribbon is sold by the meter, so we must buy whole meters. We need enough ribbon for his project, so we must round up if there are decimals.
   Full step-by-step solution

   Let's go step-by-step. --- **Step 1: Understand the problem** Liam needs: - Blue ribbon: 3.75 meters - Red ribbon: 2.25 meters Ribbon is sold by the meter, so we must buy whole meters. We need enough ribbon for his project, so we must round up if there are decimals. --- **Step 2: Add the total meters needed** 3.75 + 2.25 = 6.00 meters exactly. --- **Step 3: Check if we need to round up** Since 6.00 is exactly 6 meters, and ribbon is sold by the meter, buying 6 meters will give exactly what he needs. --- **Step 4: Conclusion** Liam should buy **6 meters** of ribbon in total. --- **Final Answer:** 6

8. Round 3.47 to the nearest tenth. Answer: 3.5 Solution: Identify the digit in the tenths place. In 3.47, the digit in the tenths place is 4. Look at the digit to the right (the hundredths place).
   Full step-by-step solution

   Step 1: Identify the digit in the tenths place. In 3.47, the digit in the tenths place is 4. Step 2: Look at the digit to the right (the hundredths place). The hundredths digit is 7. Step 3: Since the hundredths digit (7) is 5 or greater, we round the tenths digit (4) up by 1. 4 becomes 5. Step 4: The digits after the tenths place become zero, so 3.47 rounded to the nearest tenth is 3.5.

9. Liam is measuring ribbon for a school project. He needs 3.75 meters of blue ribbon and 2.25 meters of red ribbon. If the ribbon is sold by the meter, what is the total length of ribbon Liam needs to buy? Answer: 6 Solution: Identify the lengths needed. Blue ribbon: 3.75 meters Red ribbon: 2.25 meters Add the two lengths together. 3.75 + 2.25 = ?
   Full step-by-step solution

   Let's go step-by-step. Step 1: Identify the lengths needed. Blue ribbon: 3.75 meters Red ribbon: 2.25 meters Step 2: Add the two lengths together. 3.75 + 2.25 = ? Step 3: Break it down for clarity. 3.75 = 3 + 0.75 2.25 = 2 + 0.25 Step 4: Add the whole numbers first. 3 + 2 = 5 Step 5: Add the decimal parts. 0.75 + 0.25 = 1.00 Step 6: Combine whole and decimal parts. 5 + 1.00 = 6.00 Step 7: Interpret the result. The total length needed is 6.00 meters. Since ribbon is sold by the meter, Liam must buy 6 meters. Final answer: 6