Rounding
Grade 4 students learn to round numbers to the nearest ten in Saxon Math Intermediate 4 Chapter 2. The rule is simple: look at the ones digit. If it is 5 or more, round up to the next ten; if it is 4 or less, round down by changing the ones digit to 0. Maria counted 67 shells: the ones digit is 7 (5 or more), so 67 rounds up to 70. Rounding makes numbers easier to use for estimation, mental math, and everyday approximations.
Key Concepts
New Concept To round a number to the nearest ten, we choose the closest number that ends in zero.
What’s next Next, you’ll practice rounding numbers to the nearest ten and money to the nearest dollar and quarter.
Common Questions
What is the rule for rounding to the nearest ten?
Look at the ones digit. If it is 5, 6, 7, 8, or 9, round up to the next multiple of 10. If it is 0, 1, 2, 3, or 4, round down by keeping the tens digit the same and changing the ones digit to 0.
How do you round 67 to the nearest ten?
The ones digit is 7. Since 7 is 5 or more, round up. The ten above 60 is 70. So 67 rounds to 70.
How do you round 34 to the nearest ten?
The ones digit is 4. Since 4 is less than 5, round down. Keep the tens digit (3) the same and replace the ones with 0. So 34 rounds down to 30.
What does it mean to round down?
Rounding down means keeping the tens digit the same and replacing the ones digit with 0. The result is the multiple of 10 that the number was already at or above but has not yet reached the halfway point of.
What is the halfway rule for rounding to the nearest ten?
The halfway point between any two consecutive tens is the number ending in 5 (e.g., 25 is halfway between 20 and 30). Numbers at the halfway point or above always round up.
How is rounding to the nearest ten used in everyday life?
Estimating prices at a store, guessing how many people are in a crowd, reporting approximate test scores, and doing quick mental calculations all use rounding to the nearest ten.