4.NBT.3
Use place value understanding to round multi-digit whole numbers to any place.
About the Math
Rounding numbers should result in using number sense not just following a rule. Students should apply their understanding of number lines to help them round numbers. When thinking about tens, numbers with the one’s digit of 1,2,3, and 4 are closer to the lower multiple of ten. Numbers with the one’s digit of 6, 7, 8, and 9 are closer to the greater multiple of ten. Since 5 is equidistance from both multiples, it is rounded to the greater multiple of ten. This same concept applies to rounding to the nearest hundred or thousand. When teaching rounding, it is helpful for students to use a number line to visualize the process. For example, if asked to round 17 to the nearest ten, draw a number line and label the endpoints 10 and 20. Have the students place the number 17 on the number line and point out that it is closer to 20 so 17 rounds to 20. Important vocabulary for this standard includes value and digit.
Use place value understanding to round multi-digit whole numbers to any place.
- I can explain how to use digits to round a number.
- I can write a multi-digit number rounded to any place.
About the Math
Rounding numbers should result in using number sense not just following a rule. Students should apply their understanding of number lines to help them round numbers. When thinking about tens, numbers with the one’s digit of 1,2,3, and 4 are closer to the lower multiple of ten. Numbers with the one’s digit of 6, 7, 8, and 9 are closer to the greater multiple of ten. Since 5 is equidistance from both multiples, it is rounded to the greater multiple of ten. This same concept applies to rounding to the nearest hundred or thousand. When teaching rounding, it is helpful for students to use a number line to visualize the process. For example, if asked to round 17 to the nearest ten, draw a number line and label the endpoints 10 and 20. Have the students place the number 17 on the number line and point out that it is closer to 20 so 17 rounds to 20. Important vocabulary for this standard includes value and digit.