Learner Mathematics Worksheet Rounding up and down decimals ________________________________________________________________ Introduction In this activity you will learn how to round up and down decimals to two decimal places. Understanding Decimals If the decider is 5 or higher, round the number to the left up. If the decider is 4 or lower, round the number the left down. Example The example below shows you how to round decimal numbers to one decimal place: Example 1: Round 2.43243782 to one decimal place. You need to have one number after the decimal point, therefore the decider is the second number after the decimal point. If the decider is 4 or lower, the number to left will stay the same. If the decider is 5 or higher, the number to the left will be rounded up. 2.43243782 In this case, the decider is 3. The number to the left is 4, therefore, the number is rounded down to 2.4. Example 2: Round 4.46578352 to two decimal places. You need to have two numbers after the decimal point, therefore the decider is the third number after the decimal point. If the decider is 4 or lower, the number to left will stay the same. If the decider is 5 or higher, the number to the left will be rounded up. 4.46578352 In this case, the decider is 5. The number to the left is 6, therefore, the number is rounded to 4.47. 1 Activity Complete the questions on the following page by rounding the decimal numbers to either one or two decimal places. 1. Round 2.465325 to one decimal place. ……………………………………………………………………………………………………………………………………… 2. Round 6.5749 to one decimal place. ……………………………………………………………………………………………………………………………………… 3. Round 9.426 to one decimal place. ……………………………………………………………………………………………………………………………………… 4. Round 4.222222 to one decimal place. ……………………………………………………………………………………………………………………………………… 5. Round 2.6934 to one decimal place. ……………………………………………………………………………………………………………………………………… 6. Round 8.35287 to one decimal place. ……………………………………………………………………………………………………………………………………… 7. Round 8.21475 to one decimal place. ……………………………………………………………………………………………………………………………………… 8. Round 7.8296 to one decimal place. ……………………………………………………………………………………………………………………………………… 9. Round 3.895 to one decimal place. ……………………………………………………………………………………………………………………………………… 10. Round 8.389847 to one decimal place. ……………………………………………………………………………………………………………………………………… 11. Round 4.64839 to two decimal places. …………………………………………………………………………………………………………............................... 2 12. Round 93.486579 to two decimal places. ……………………………………………………………………………………………………………………………………… 13. Round 1.111111 to two decimal places. ……………………………………………………………………………………………………………………………………… 14. Round 4.556578 to two decimal places. ……………………………………………………………………………………………………………………………………… 15. Round 7.23755 to two decimal places. ……………………………………………………………………………………………………………………………………… 16. Round 5.55578 to two decimal places. ……………………………………………………………………………………………………………………………………… 17. Round 2.985 to two decimal places. ……………………………………………………………………………………………………………………………………… 18. Round 3.235 to two decimal places. ……………………………………………………………………………………………………………………………………… 19. Round 16.484 to two decimal places. ……………………………………………………………………………………………………………………………………… 20. Round 8.889 to two decimal places. ……………………………………………………………………………………………………………………………………… Outcome ______________________________________________________________________________________________________ You should now feel confident in rounding decimals to one or two decimal places. You should now understand the following: You must locate the decider to determine whether to round up or down. If the decider is 5 or higher, round the number to the left up. If the decider is 4 or lower, round the number the left down. 3
