Rounding Decimal Numbers
Rounding decimal numbers simplifies values to a specified place value in Grade 6 math (Saxon Math, Course 1). The rule: look at the digit immediately to the right of the target place. If it is 5 or greater, round up (increase the target digit by 1); if it is 4 or less, round down (keep the target digit). For example, rounding 4.678 to the nearest tenth: the digit in hundredths is 7 (≥5), so round up: 4.7. Rounding to the nearest hundredth: 4.678 → 4.68. Rounding is used in money (to the nearest cent), measurement estimates, and making large decimal computations manageable.
Key Concepts
New Concept To round a decimal, look at the digit to the right of the target place. If this digit is 5 or greater, round up; otherwise, round down. What’s next Now, you'll apply this rule in worked examples for rounding to different place values, including money, and see how it's used for estimation.
Common Questions
What is the rule for rounding decimal numbers?
Look at the digit one place to the right of where you are rounding. If it is 5 or more, round up; if it is 4 or less, keep the digit unchanged (round down).
How do you round 3.847 to the nearest tenth?
The hundredths digit is 4 (less than 5), so keep the tenths digit: 3.8.
How do you round 3.852 to the nearest tenth?
The hundredths digit is 5 (5 or more), so round up the tenths digit: 3.9.
How do you round a decimal to the nearest whole number?
Look at the tenths digit. If 5 or more, round the whole number up; if 4 or less, keep the whole number. For example, 7.6 rounds to 8; 7.4 rounds to 7.
Why is rounding useful in real life?
Rounding makes numbers easier to work with for estimates, money ($9.85 ≈ $10), and reporting measurements to appropriate precision.