Comparing and Rounding Decimals
Rounding decimals keeps a set number of decimal places. Look at the next digit. If it is 5 or more, round up. If it is less, round down. Comparing decimals lines up the points, then reads left to right.
Video Lesson
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Flashcards
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What Is Decimal Place Value?
- The 1st, 2nd, and 3rd decimal places are tenths, hundredths, thousandths.
- For example, .
Rounding Decimals Rules
- Look at the digit one place to the right of the rounding place.
- If it is less than 5, round down. If it is 5 or more, round up.
- For example, 12.348 rounded to the nearest tenth is 12.3, because the digit in the hundredths place is 4, which is less than 5, so we round down.
Comparing Decimals
- Line up the decimal points first.
- Compare digits from left to right.
- The number with the larger digit first is greater.
Practice Questions
Test your understanding
Round 3.47 to 1 decimal place.
Correct! 🎉 +10 pointsNot quite right
To round 3.47 to 1 decimal place, check the second decimal. Since 7 is greater than 5, round 3.4 up to 3.5.
Which number is greater, 0.66 or 0.58?
Correct! 🎉 +10 pointsNot quite right
0.66 is greater because 66 hundredths is larger than 58 hundredths.
Round 7.657 to 2 decimal places.
Correct! 🎉 +20 pointsNot quite right
To round 7.657 to 2 decimal places, check the third decimal. Since 7 is greater than 5, round 7.65 up to 7.66.
Round 18.569 to the nearest hundredth.
Correct! 🎉 +20 pointsNot quite right
To round 18.569 to the nearest hundredth, check the thousandth digit. Since 9 is greater than 5, round 18.56 up to 18.57.
Which number is greater, 0.441 or 0.435?
Correct! 🎉 +20 pointsNot quite right
0.441 is greater because when comparing digit by digit, the tenths are both 4, but the hundredths digit of 0.441 is 4, which is larger than the hundredths digit of 0.435, which is 3.
Round 9.895 to 2 decimal places.
Correct! 🎉 +30 pointsNot quite right
To round 9.895 to 2 decimal places, check the third decimal. Since 5 is 5 or more, round 9.89 up to 9.90.
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Interactive Activity
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Students Also Ask
The questions students bump into most on this topic
In 12.348, the digit 3 sits in the 1st decimal place (tenths). The digit 4 sits in the 2nd decimal place (hundredths). The digit 8 sits in the 3rd decimal place (thousandths). Each place represents a smaller fraction of one as you move right of the decimal point.
Rounding to 2 decimal places means keeping only two digits after the decimal point and removing the rest. Look at the digit in the 3rd decimal place. If it is 5 or greater, add 1 to the 2nd place digit. If it is below 5, leave the 2nd place digit unchanged. Then remove all digits to the right.
Round up when the digit one place to the right of the desired decimal place is 5 or greater. Then add 1 to the digit at the desired place. Round down when that digit is below 5, and keep the digit at the desired place unchanged. Then remove all digits to the right.
Write the two decimals one below the other so their decimal points line up vertically. Compare the digits at the same place value, working from left to right. The first position where the digits differ decides the comparison. The decimal with the larger digit at that position is the larger one.