Over the past few years, my approach to teaching rounding has followed a similar path. The choice of methodology was often influenced by the adopted textbook within a school district. I would generally guide students to place numbers on a number line and determine their proximity to the nearest value. The class would focused on rounding to the nearest tens, gradually progressing to hundreds and eventually expanding to larger place values.
We would introduce a rule that involved underlining the digit to the right of the one being rounded. The rule states that if the underlined digit is “5 or more, round up; if it’s 4 or less, keep it the same.” I believe this has even been turned into a song at some point. This linear progression served as the foundation for teaching rounding at the early elementary level.
This year brought about a change in our district as elementary teachers adopted a new resource. The emphasis shifted to exploring the value of numbers even before delving into the concept of rounding. Students were tasked with identifying the value of specific digits and ordering them, whether from greatest to least or vice versa. We incorporated the use of base-ten blocks and relied on expanded form extensively to help students develop a deeper understanding of number formation and the impact of place value on value itself. Students became more familiar with the value associated with each digit within a four or more digit number.
Students began identifying the closest multiple of a given number. For instance, they would determine the nearest multiple of 10,000 for a number like 432,000. This transition was seamless because students had already explored multiples and factors earlier in the year. Understanding how multiples relate to rounding was a novel approach and it resonated well with the students. Now, when asked to round to a specific digit, students consider the nearest multiple, which seems to make more sense to them. I am excited to continue using a similar rounding teaching strategy moving forward.