Before this lesson, students named multiples of 10 and multiples of 100 that are near given numbers and identified the multiple of 10, or the multiple of 100, that was closest. They located numbers on a number line and approximated their distances from adjacent tick marks that indicate tens, or from endpoints that mark hundreds.

Here students learn that sometimes, when we round to the nearest ten and the nearest hundred, we round to the same number. Students also learn that when numbers are right in the middle of two multiples of 10 or two multiples of 100, the convention is to round up. Students use rounding to estimate the number of students in a school and see that rounding to the nearest ten and the nearest hundred can give different estimates for the same situation.

How is your students’ understanding of place value contributing to their work rounding to the nearest ten and the nearest hundred?