Zero on the Rounding Roller Coaster and my Growth Mindset Moment

Rounding roller coaster in a 5th grade math word wall

This past week I had to do a fair amount of pride-swallowing to hear some critical feedback. This often seems to happen when I post on Facebook!

This time it was about this seemingly innocuous rounding roller coaster in my 5th grade math word wall. I left out the zero on purpose. After all, 1.70 is the same as 1.7, right? So we're not really rounding it. Right? 



A teacher gave the example 1.2505 with the direction to "round to the nearest 2 decimal spots". 1.25 is the same as 1.250, so are we really rounding? This exact thing opens up a great conversation to have with kids about the placement of 0 in numbers. Every year I have seniors who insist on typing ".20" for 20%. They are super uncomfortable with .2 being the same as .20. Why?

This teacher and I talked (commented back and forth, really since it was Facebook) for a while. Place value came up. I teach my students that if a 0 is between the decimal and the nonzero numbers ("sig figs", science people?) it matters whereas a 0 on either end doesn't matter. I like to show this hilarious check photo posted on Reddit




It's still just 4 bucks.


But then the teacher threw me a curve ball, which was when my growth mindset needed kicking into high gear. 

"Round 207 to the nearest hundred"

I suddenly saw the value of a 0 on the rounding roller coaster. To round to the hundred we look to the next digit, see it's a zero and drop the rest like a sack of hot potatoes. That zero is not on the end and therefore does matter. It matters a whole lot! I decided to add in an alternate roller coaster with the zero.

Rounding roller coaster in a 5th grade math word wall

It's hard for me to post a photo of something I've created only to have it picked apart. But it's also so good! The criticism, though super painful and uncomfortable at first, has allowed me to create these word walls in the best way possible for students. I appreciate the help to do this so much.

You can check out this 5th grade math word wall, as well as word walls for 6th grade, 7th grade, 8th grade, algebra, geometry and algebra 2 in the math word walls section of my Teachers pay Teachers store.

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