What is Rounding Decimals?

Rounding decimals is a way of simplifying a number by changing it to a nearby, more convenient value. We often round numbers so they are easier to work with, especially when we don’t need an exact answer.

Why Rounding is Useful

Rounding makes it easier to add, subtract, or compare numbers. It helps us estimate values in everyday life, like shopping or measuring.

Key Rules for Rounding Decimals

  1. Identify the Place Value: Decide which decimal place you want to round to. It could be the nearest whole number, tenths, hundredths, etc.
  2. Look at the Next Digit: Check the digit immediately to the right of the place value you are rounding to.
  3. Apply the Rounding Rules:
    • If the digit is 0, 1, 2, 3, or 4, you round down. This means you keep the digit you are rounding the same and turn all digits to the right into zeros.
    • If the digit is 5, 6, 7, 8, or 9, you round up. This means you add 1 to the digit you are rounding and turn all digits to the right into zeros.

Example of Rounding Decimals

Let’s say we want to round the number 3.67 to one decimal place:

  1. Identify the Place Value: We want to round to one decimal place (the tenths).
  2. Look at the Next Digit: The digit in the tenths place is 6, and the next digit (hundredths place) is 7.
  3. Apply the Rounding Rule: Since 7 is greater than 5, we round up. So, 3.67 becomes 3.7.

Tips and Tricks

  • Use a number line: Visualise where the number lies between two whole numbers.
  • Practice with real-life examples: Round prices or measurements to make it more relatable.
  • Check your work: After rounding, think about whether your rounded number makes sense in the context.

Questions on Rounding Decimals

Easy Level Questions

  1. Round 2.3 to one decimal place.
  2. Round 5.9 to one decimal place.
  3. Round 7.14 to one decimal place.
  4. Round 4.56 to one decimal place.
  5. Round 9.01 to one decimal place.
  6. Round 3.4 to one decimal place.
  7. Round 8.8 to one decimal place.
  8. Round 6.25 to one decimal place.
  9. Round 1.73 to one decimal place.
  10. Round 0.49 to one decimal place.
  11. Round 2.5 to one decimal place.
  12. Round 3.8 to one decimal place.
  13. Round 0.99 to one decimal place.
  14. Round 4.1 to one decimal place.
  15. Round 5.55 to one decimal place.
  16. Round 3.6 to one decimal place.
  17. Round 7.4 to one decimal place.
  18. Round 1.2 to one decimal place.
  19. Round 9.8 to one decimal place.
  20. Round 2.75 to one decimal place.

Medium Level Questions

  1. Round 4.763 to two decimal places.
  2. Round 6.349 to two decimal places.
  3. Round 5.678 to two decimal places.
  4. Round 3.141 to two decimal places.
  5. Round 8.999 to two decimal places.
  6. Round 7.056 to two decimal places.
  7. Round 2.485 to two decimal places.
  8. Round 9.812 to two decimal places.
  9. Round 1.234 to two decimal places.
  10. Round 0.567 to two decimal places.
  11. Round 2.999 to two decimal places.
  12. Round 5.230 to two decimal places.
  13. Round 4.876 to two decimal places.
  14. Round 6.151 to two decimal places.
  15. Round 3.889 to two decimal places.
  16. Round 7.641 to two decimal places.
  17. Round 0.055 to two decimal places.
  18. Round 5.625 to two decimal places.
  19. Round 1.905 to two decimal places.
  20. Round 8.485 to two decimal places.

Hard Level Questions

  1. Round 4.7863 to three decimal places.
  2. Round 6.3498 to three decimal places.
  3. Round 5.6789 to three decimal places.
  4. Round 3.1415 to three decimal places.
  5. Round 8.9997 to three decimal places.
  6. Round 7.0564 to three decimal places.
  7. Round 2.4856 to three decimal places.
  8. Round 9.8123 to three decimal places.
  9. Round 1.2345 to three decimal places.
  10. Round 0.5678 to three decimal places.
  11. Round 2.9999 to three decimal places.
  12. Round 5.2300 to three decimal places.
  13. Round 4.8765 to three decimal places.
  14. Round 6.1512 to three decimal places.
  15. Round 3.8894 to three decimal places.
  16. Round 7.6410 to three decimal places.
  17. Round 0.0551 to three decimal places.
  18. Round 5.6254 to three decimal places.
  19. Round 1.9056 to three decimal places.
  20. Round 8.4859 to three decimal places.

Answers

Easy Level Answers

  1. 2.3
  2. 5.9
  3. 7.1
  4. 4.6
  5. 9.0
  6. 3.4
  7. 8.8
  8. 6.3
  9. 1.7
  10. 0.5
  11. 2.5
  12. 3.8
  13. 1.0
  14. 4.1
  15. 5.6
  16. 3.6
  17. 7.4
  18. 1.2
  19. 9.8
  20. 2.8

Medium Level Answers

  1. 4.76
  2. 6.35
  3. 5.68
  4. 3.14
  5. 9.00
  6. 7.06
  7. 2.49
  8. 9.81
  9. 1.23
  10. 0.57
  11. 3.00
  12. 5.23
  13. 4.88
  14. 6.15
  15. 3.89
  16. 7.64
  17. 0.06
  18. 5.63
  19. 1.91
  20. 8.49

Hard Level Answers

  1. 4.786
  2. 6.350
  3. 5.679
  4. 3.142
  5. 9.000
  6. 7.056
  7. 2.486
  8. 9.812
  9. 1.235
  10. 0.568
  11. 3.000
  12. 5.230
  13. 4.877
  14. 6.151
  15. 3.889
  16. 7.641
  17. 0.055
  18. 5.625
  19. 1.906
  20. 8.486

With practice, rounding decimals will become easier and more familiar! Happy rounding!