This question from a PARCC math practice assessment requires students to understand rounding.
To round to the nearest ten, underline the place you are rounding to, look to the right, ten and above, give it a shove, four or below, go down low! I once spent an entire hour with an elementary class comprised of pretty sharp kids and an abundance of enthusiasm who could not explain what the rounding chant really meant.
There are imprecise elements to this rounding chant, as well as this question found on the PARCC practice math assessment. In the PARCC questions we are asked to round three numbers to the nearest ten. Fair enough and likely matched to the discourse on rounding we hear, consistently, about rounding to the nearest ten or tens place…are we not really and literally choosing a next higher, or lower, multiple of ten? And should we use this precise language when teaching children about rounding numbers to the closest whole number multiple of 10 or100…
Rounding on a number line is a common practice in elementary math class. If we listen closely, we can hear teachers telling students to round up, or down, to the next ten, hundred, thousand, and so on ( although we mean to the next multiple of ten, hundred…) using a horizontal number line. In an unabashed plug for Engage NY, I just love that rounding is introduced and practiced using a vertical number line. Engage NY Module 3, Lessons 12 – 14 use the language of place value to help students understand rounding. Instead of saying 73, we will say 7 tens and 3 ones to understand the location of 73 on a number line having 70 and 80 as endpoints.
Illustrative Mathematics has several content rich tasks to support student learning of the 3rd grade math standard for rounding numbers. Click on the links below for the tasks!
3.NBT Rounding to the Nearest Ten and Hundred
3.NBT, 4.NBT Rounding to the Nearest 100 and 1000
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