Rounding Whole Numbers
Rounding whole numbers produces friendlier estimates by adjusting to a target place value. In Grade 6 Saxon Math Course 1, the rule is: find the target digit, look one place to its right — if that digit is 5 or more, increase the target by 1; if 4 or less, leave it unchanged. Replace all digits to the right with zeros. Rounding 78,341 to the nearest thousand gives 78,000 (the hundreds digit is 3 < 5). Rounding is essential for estimation, mental math, and checking the reasonableness of answers.
Key Concepts
New Concept When we round a whole number, we are finding another whole number, usually ending in zero, that is close to the number we are rounding. What’s next This card introduces the core idea of approximation. Soon, you'll work through examples on rounding to different place values and applying estimation to solve practical problems.
Common Questions
What is the rounding rule?
Look at the digit one place to the right of your target. If 5 or more, round up. If 4 or less, keep the target unchanged. Replace digits to the right with zeros.
Round 78,341 to the nearest thousand.
Thousands digit is 8; digit to right is 3 (< 5); keep 8. Answer: 78,000.
Round 4,762 to the nearest hundred.
Hundreds digit is 7; digit to right is 6 (≥ 5); round up to 8. Answer: 4,800.
Round 5,500 to the nearest thousand.
Thousands digit is 5; digit to right is 5 (≥ 5); round up to 6. Answer: 6,000.
Why is rounding useful in everyday situations?
Rounding makes numbers easier to work with mentally — saying a $47 item costs 'about $50' is faster and close enough for estimation purposes.