YOU ARE LEARNING:
Rounding to a number of decimal places gives us the opportunity to simplify complicated numbers after the decimal point.
Rounding decimals to a number of decimal places allows us simplify numbers, while reducing their accuracy. This helps to make numbers more readable in everyday contexts.
Rounding to decimal places follows the same rules as rounding whole numbers. If a digit is greater than 5, then we round up the digit to the left. If the digit is less than 5, the we round down the digit to the left.
For example, let's try rounding 23.45357 to 3 decimal places
Choose the number to round
As we are looking to round to 3 decimal places, we need to round the 3rd digit after the decimal point: 23.45357
Look at the digit to the right of it
The digit to the right controls whether it rounds up or down. As 5 is 5 or greater, we need to round up ⬆️
Round up the 3rd digit after the decimal
23.45357 rounds up to 23.454
Let's try rounding to 2 decimal places
To 2 decimal places, we need to round the 2nd digit after the decimal point 23.45357
Look at the digit to the right
This time, the digit to the right is 3, which is less than 5. This means that we do not round the 2nd digit at all.
Cut off the decimal after the 2nd decimal place
To 2 decimal places, 23.45357 rounds to 23.45
Round 23.4543 to 3 decimal places
Round 45.483 to 2 decimal places
What if we wanted to round 0.999 to 2 decimal places? We need to round up, but what do we round up to?
Let's try rounding 0.999 to 2 decimal places
Look at the number
0.999 indicates that we need to round up the 9
Round the 9 up
9 rounds up to 10, so it also affects the digit to the left. So, 0.999 becomes 1.00 as there are two 9's. We keep the two 0's so that the number keeps 2 decimal places.
0.999 to 2 decimal places is 1.00
Let's try rounding 0.899 to 2 decimal places
This time, there is only one 9. Therefore, we round up in the same way, but this time the answer is 0.90
What is 0.798 to 2 decimal places?
What is 0.395 to 2 decimal places?