Rounding to decimal places

We can round numbers to the nearest n decimal places using these steps:

1. Find the digit at the nth decimal place.
2. Check if the number after that is less than 5:
   • If less than 5, you are rounding down, so keep the nth decimal place the same.
   • If more than or equal to 5, you are rounding up, so increase the nth decimal place by one (if it is 9, it becomes 0 and you carry 1 to the left, where you do the same).
3. Remove all digits after the nth decimal place.

Examples

Round 3.14159 to 2 decimal places

• 2nd decimal place is 4.
• The number after that is 1.
• 1 is less than 5, so we round down and keep the 4 the same.
• Remove all digits after the 2nd decimal place, giving 3.14.
• Answer: 3.14.

Round 2.71828 to 3 decimal places

• 3rd decimal place is 8.
• The number after that is 2.
• 2 is less than 5, so we round down and keep the 8 the same.
• Remove all digits after the 3rd decimal place, giving 2.718.
• Answer: 2.718.

Round 1.98765 to 4 decimal places

• 4th decimal place is 6.
• The number after that is 5.
• 5 is equal to 5, so we round up and increase the 6 by 1 to get 7.
• Remove all digits after the 4th decimal place, giving 1.9877.
• Answer: 1.9877.

Round 0.798 to 2 decimal places

• 2nd decimal place is 9.
• The number after that is 8.
• 8 is more than 5, so we round up and increase the 9 by 1 to get 10.
• Since 9 becomes 10, we set the 2nd decimal place to 0 and increase the 1st decimal place by 1 (which is 7) to get 8 (so now we have 0.80...).
• Remove all digits after the 2nd decimal place, giving 0.80.
• Answer: 0.80.