Dividing by 2-Digit Numbers (Day 1)

4 teachers like this lesson
Print Lesson

Objective

Students Will Be Able To use prior knowledge to divide 2-digit numbers. Students will use expanded form of numbers to better understand division and how it works.

Big Idea

The Standard algorithm uses the expanded form of numbers!

Language Objective and Prior Knowledge

Language Objective: Students will use academic language when explaining their thinking center on division. Examples: divisor, dividend, quotient, and remainder.

Prior Knowledge: Multiplication facts, basic division skills, rounding and estimation.

Math Blast - Lesson Activator

15 minutes

MathBlast 22 Number of the Day 

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's Soup Cans

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: Using different methods for dividing, using long division and estimation.  2 dig x 2 digs

So today we are starting to take what we’ve been learning about division with powers of 10s, 100s, and 1000s. And we’re going to work in what we’ve learned with rounding and estimating.

But we are going to do some things different. Instead of rounding and estimating after we’re done with a problem, we’re going to do it first to help us get started.

For example, lets say we have 97 of those great honey crisp apples from my grandfather’s orchard and he need to put them into 15 bags, so 97 ÷ 15, now I know that 2 x 15 is 30, 4 x 15 is 60 and 6 x 15 is 90: so I am going to start with 6 as part of my quotient. 

Set up the long division bar and start the math. It’s easy because we’ve already done the multiplication of 6 x 15 = 90. You’ll end up with a reminder of 7.

So we were able to put 6 apples in each of the 15 bags and I took the last seven apples home because they were left over!  heheheh

Work It Out

40 minutes

Have students take a clean piece of paper or in their math notebooks. Divide the paper into 6 equal sections. Write the following problems on the board. In the left section they will write the original problem and estimate the answer and in the section on the right they will do long division

Estimate

Long Division

23 ÷ 10

 

47 ÷ 12

 

67 ÷ 31

 

If people finish early, have them become EXPERTS and help students that need support. Make sure to check-in to check to make sure people are estimating. Those students that know long division will skip the estimating part but that is not following directions which means their work is technically wrong!

I give struggling learners a multiplication chart that goes up to 25. This is really helpful and takes some pressure off them because it allows them to access the content and purpose of this lesson.

Closing The Deal

10 minutes

Bring the class together, this should be a great opportunity to talk about estimating and division, why is it helpful?

Does it take the stress out of division? What struggles are people still having?

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.

Quick Assessment

5 minutes

The Post-It PosterHave students round, estimate then solve using long division:

47 ÷ 5 =      

Teaching tip: Since 45 ÷ 5 = 9, students should start with 9 as their divisor. They should see that when they round 47 to 50, 10 is too big to be a divisor of the original number.

The Quick Assessment is supposed to be quick and on the easy to medium difficulty level. You are checking to see if students understand 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.