Multiplying by 10s: The Power of 10s (Day 1)

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Students Will Be Able To identify a pattern when multiplying by 10s, and then break apart a two-digit number to multiply by powers of 10 to find products.

Big Idea

By breaking apart a two-digit number students can more easily find the product.

Language Objective and Prior Knowlege

Language Objective: Students will be able to take a two digit number and put it into extended form in order to simplify multiplication steps.

Prior Knowledge: Basic knowledge of multiplication facts.

Math Blast - Lesson Activator

15 minutes

MathBlast 14 Number of the Day 14

Math Blast is a quick, fun, fast-paced math game! Every day starts with a Number of the Day. This is the tool I use to not only recall, reteach and pre-teach but it is my way to start classroom management. Students know the expectations of how to come in and get right to work. I do not have to spend any time waiting for students to get ready. Class starts immediately. And since I include music students are really engaged. I also encourage students to support each other for those struggling learners. This is also a great vehicle to expose students to concepts that I know will show up in state testing so that when we do get to these lessons students have already seen the work. Math Blast’s progression goes from easy to hard on the difficulty scale!

Students use a white board and divide it up as follows:


This space students write in the number of the day.



This section is the factors of the number of the day.


This section the students put the number of the day over 100.



This section students write if the number is Prime, Composite or Square.


Using the fraction, students write it as a decimal and a percentage.


This section the students put the above fraction in Lowest Terms if possible.


See, Think, Wonder

5 minutes

Andy Warhol Marilyn Monroe, Large

I end Math Blast and lead into my lesson with a See, Think, Wonder. The art is choose always relates to the unit I am teaching. It is a real fun way to get your students to think deeper about a subject without them knowing that they are doing it.

The SEE part is pretty basic thinking, I see….

The THINK part gets them thinking a little deeper. This art makes me think about….

And the WONDER gets them really thinking deeper. This art makes me wonder if…. It is my way to getting their brains ready to think about math and I find that the transition is great. It is also a quick chance to expose my students to different types of art.

Note: You don’t have to use art; I use art because I am passionate about art. Use examples of things that ignite your passion!

The Elevator Speech

10 minutes

Concept: Draw up on the white board some simple one digit by one digit multiplication. After that next to each do the same problem but make the second single digit into a base 10 (for example: 3 would become 30) as a class talk about if there are any patterns that we are seeing. Another way I like to show students is to take, say, 231 and have them add it up ten times. Since adding and multiplying are basically the same, it will add up to 231, or 213 x 10.

Script, if needed: (once you have demonstrated a pattern for multiply by 10s) Let’s conduct an experiment. Say we had super natural powers and we never got tired. Let’s count how many times we can hop in one place for a minute. Make sure you count the total in your head. (get a timer and say GO!) Now, to make our work easier we’re going to round that number to the nearest 10s place (this will help them work with powers of 10s) ok, now record that data on a piece of paper. Now because we don’t have all day to do this we are going to do some estimation to find out how many hops we could do in a day’s time! First let’s start by calculating how many we could do in an hour, who knows how we could figure that out. (x 60 minute in an hour) Now let’s figure out how many we could do in a day (x 24 hours in a day, for the purposes of Power of 10 I rounded 24 to be 20).

Work It Out

40 minutes

Have students figure write out 6 problems of their own on a piece of paper. Then instruct them that they are to write the answers on a separate piece of paper.

These math problems should be made up of two 2-digit numbers, one of which should be a 10s number (ex: 34 x 20) Give them some time to get these created, check in. Once people have the work done they will switch papers with their table group. Once that person is done have them hand the paper back for the original author to grade. 

Closing The Deal

10 minutes

The Closing It section of the lesson is very important. This opportunity allows you to bring the class back together and have them make the connection to the learning objective of the day. You should also make sure that you make a connection to the word of the day. This closing gives students the opportunity to make the connection to the launch and they work that they did. It is also another chance to give a quick formative assessment to check for understanding.

Bring it all back around and talk about why x10s works, ask students is there a short cut that they can do when they see one of the multipliers ends in a zero?

Quick Assessment

5 minutes

The Post-It Poster: Round only ONE of the following numbers to estimate an answer 38 x 21.

The Quick Assessment is supposed to be quick and on the easy to medium difficulty level. You are checking to see if students are understanding the basic concept of the lesson. If you make the problem difficult you are adding a different level of assessment. If you are teaching a higher level class adding a difficult layer might be appropriate but please note that I do not find it necessary to add this level.