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.

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.

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.

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, including the new interactive digital version, in the math word walls section of my Teachers pay Teachers store.

Actually, a zero on the end of a decimal does matter because it implies the level of precision to which something has been measured. For example, you might write 1.25g because your scale only measured to the nearest hundredth of a gram. The actual mass could be anywhere between 1.245 and 1.254. By writing 1.250, you are stating that you are measuring to the nearest thousandth and the actual mass is between 1.2495 and 1.2504. In science, this is a hugely important distinction.

ReplyDeleteRight, which is what this post is all about:)

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