## 5.NBT.2: Explain patterns in the number of zeros of the product when multiplying a number by powers of 10, and explain patterns in the placement of the decimal point when a decimal is multiplied or divided by a power of 10. Use whole-number exponents to denote powers of 10.

**UNPACKED EXPLANATION:**This one is fairly straight forward. This standard is commonly known as "the powers of 10," so keep that in mind. It's all about base 10 and understanding that you're multiplying by ten each time you move to the next larger place value, with an understanding of the opposite function of adding a 0, which is removing a zero, while understanding conceptually that removing a 0 means the decimal point has moved a place to the left. Finally, exponents are a great way to have students denote these relationships, and starts building upon skills they'll use a lot further on down the road.

**WHAT THE PARCC WILL EXPECT:**The PARCC Practice Test site does not have specific problems for 5.NBT.2, but when looking closer at this standard, students will need to be familiar with problems that resemble the following:

- 34 x 10,000 =
- 90,000 ÷ 30 =
- 0.00034 x 10,000 =
- Check out this collection of videos from LeanZillion that explains the entire process of powers of 10.

**RESOURCES**

- First off, a lot of the things I referenced in my post for 5.NBT.1 are relevant to this standard as well. So check that out: 5th Grade Math Resources for CCSS 5.NBT.1.
- Some practice problems at Orglib.com: This is a great site where you can make an account, build tests from a bank of questions, and even track student results. It's one of the closer things I've found that can mimic the PARCC assessment.
- Even though it's in my last post, this is a spot on activity for this standard:
- Place value cups (click the link for instructions): This simple activity is very concrete for kids, and if you keep a few handy, they're good for reference later in the year for students who didn't retain everything they learned during the teaching of 5.NBT.1.
- Powers of 10 Yahtzee: Although I linked to the Google Doc here, I'll go ahead and explain this game in my own words:
- Power of 10 Yahtzee should be played in pairs. Students should already have an understanding of exponents and how to navigate a place value chart. Each player is going to roll the dice. Whatever number player A rolls they will put it as an exponent to the base number 10 (if they roll a 4, they will be finding the product of 10 to the power of 4, or 10,000). Then player B goes. They do this 5 times, and add up their totals, whoever has the highest total wins. A more rigorous extension of this game for the advanced student would be to have each student roll two dice (preferably different colored dice would work), and have one color be the base number and the second be the exponent).
- IXL Listing of Problems that Fit the Standard
- The following listing is for worksheets:
- Mathworksheetland.com 5.NBT.2 Listing: A great starting point. Why make your own worksheets when there's already practice stuff out there. If you know how, you can send these right to an iPad and have kids do some practice there, or print them out.
- Mrmaffesoli.com Printables: I use these, good stuff for sure.

## Vocabulary

I'll list a few sites that have good 5.NBT.2 vocabulary. I can't really even begin to say how important it is to teach students not only what academic vocabulary words mean, but how to use them in context. There's a lot of power in having students state their reasoning academically that goes beyond testing and helps reinforce the ideas they're learning about.

- A great pdf at what's a great go to resource for vocabulary, duplinschools.net.
- UEN.org resource file with vocabulary.

## 5.NBT.2 Video

The first two videos are of Khan Academy explaining both multiplying and dividing by powers of 10:

Multiplying by Powers of 10

Dividing by Powers of 10

Lastly, the STEM teacher in me can't resist putting up this video that explains what exponential growth is really all about in a scientific regard. I give to you now, Cosmic Voyage, narrated by Morgan Freeman:

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