Episode 173: Using Number Lines to Round Numbers – Rounding Numbers Series

Video about the 4 Number Relationships
Number Paths Video
John SanGiovanni’s book  Daily Routines to Jump-Start Math Class

Welcome fellow Recovering Traditionalists to Episode 173: Using Number Lines to Round Numbers –  Rounding Numbers Series

I got a question sent in to me and I thought I’d just address it here on the podcast.  Here is what was sent in: “Some of my kiddos have trouble telling me which tens a number is between.  For example, I’ll give them 53 and ask them to round it, but they can’t say it’s between either 50 or 60.”

This is actually very common and is rooted in the fact that kids are seeing numbers in isolation and haven’t built relationships around numbers.  We can’t jump into rounding if students haven’t spent time exploring how numbers relate to each other because that’s all that rounding really is.  

My advice for how to help students is not an answer I can give in a short podcast. So I’ll be doing a few episodes to give my top tips to help you build your students’ number sense to help them round numbers with understanding and not just a procedure.

I know rounding is usually taught as a Place Value concept but I no longer see it that way.  Yes, I used to teach my students exactly like these Anchor Charts…for those of you listening instead of watching the video they say:

I don’t want to bash on these but I do want to acknowledge that we’ve all used them, we thought we were doing a good thing to help our students…but let’s also acknowledge that they are very procedural and give kids a set of steps to memorize & follow instead of actually helping them understand and build relationships between numbers.

So as Recovering Traditionalists what should we do instead?

Do lots and lots of activities that build Number Relationships.  

If you are new here and don’t know what those are I’ll link up a video I have about the 4 Number Relationships. But for now I’m assuming you know what those are and you want some ways to help your students build them that will lead to them being able to then round numbers easily and with understanding, not a procedure.

My first tip for helping your students with rounding by building number relationships is to Make it Visual.  

Just having the bare numeral on a piece of paper is not good.  Of course they will encounter rounding problems like that but by helping them build a visual, that visual is something they can conjure up in their mind anytime they need it.  For example when I think of needing to round 265, I’m visualizing in my mind a number line.  But what numbers go on that number line depend upon what I’m rounding it to…am I trying to figure out what 100 it’s nearest or what ten?  If it’s hundreds then I’m visualizing 200 and 300, if it’s tens then I’m seeing 260 and 270.

The original question I got, she said her students wouldn’t know what numbers to put on the number line…they don’t know what numbers the original number would be between.  So when you are starting out with number lines (or number paths) we aren’t jumping straight into rounding problems on a number line.  No, instead you are just working on getting them familiar with number lines and placing numbers on number lines.

In John SanGiovanni’s book Daily Routines to Jump-Start Math Class he has a couple routines that focus on using Number Lines.  This summer Rosalba and I created a set of routines for members of the Build Math Minds PD site and in the Number Lines ones you have routines where…..

So first thing I’d like you to do is do lots of work with number lines (or number paths if you teach Kindergarten or 1st grade).  Kids should be very comfortable using number lines and be able to visualize them even when the number lines aren’t drawn out in front of them.  They should be able to place numbers on a number line given two endpoints, or if you have a number on the number line they should be able to tell what the endpoints are.  This will get them started on their path to building number relationships and their understanding of the number line or number path that will then lead into them being able to use number lines to help them round numbers.

If you are a member of the Build Math Minds PD site, you have access to those Number Line Routines and so much more to help you build these ideas with your students.  If you aren’t a member, go over to BuildMathMinds.com/BMM to join.

Until next week my fellow Recovering Traditionalists, keep building math minds.

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