Using a Calculator Properly: Great Tool for Checking Your Work!

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Students Will Be Able To use calculators properly as a tool to support their learning and use a calculator to check their work.

Big Idea

Checking your work is essential to precision!

Language Objective and Prior Knowledge

Language Objective: Students will use correct academic language, instead of ‘times’ students will use multiply, multiplication, product. Students will use correct terms for division: divisor, dividend, quotient, remainder, difference.

Prior Knowledge: Basic Single-Digit and Double-digit multiplication, Single divisor division.

Math Blast - Lesson Activator

15 minutes

Math Blast 13 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 Dollar Sign

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

The concept I'm focusing on today is developing student understanding that calculators are a great tool for checking our work. They should know that calculators are not cheating! They also need to know that calculators aren't always correct. The information a calculators gives is only as good as the information entered.

*This is a great place for a teacher to talk about ‘legal’ cheating. (My students love it when I tell them I’m going to let them cheat on something, hehe.)

I start this lesson talking about my former life as a men’s fashion designer. I talk about designing a shirt and needing to know how much fabric it takes to make one shirt. Now when a store comes into the showroom and places an order, I’m going to need to know how much fabric to order. So, say I have this shirt that takes four yards of fabric to cut, sew, and make.

Now Macy’s comes into the showroom and places an order for 2534 shirts for all their stores on the east coast and 2677 shirts for their stores on the west coast. And now I have to call the factory in Hong Kong to order my fabric.

  1. First I would estimate my order 4 x 2500 and 4 x 2700
  2. Then use a calculator to do the actual math, I like to make a mistake here in the calculation to get a conversation going. Maybe challenge a student to use a calculator to do the work and compare.

Then I say: The next day, Nordstrom comes in and ask if they can get 4522 shirts for all of their stores across the USA. Now I know that I order additional fabric from the mill so I need to know if I can get this order out of the fabric I have left. I know I have 18,000 yards of fabric left, how can I figure out if I can fill this order. (students will either use multiplication but try to get them to think division: 18,000 / 4.

Work It Out

40 minutes

Scavenger Hunt: I create a list of math problems (+, -, x, /) and answers around the room. Under each answer I have a letter. For each answer I create a 5” x 5” card out of colored paper. On one side I write the answer to each problem, on the backside I write a letter that corresponds to the answer sheet. (hint: I go through the problems and find the 5-8 problems that I know students might have trouble with and make cards for these with a frown face L on the back) Students collect letters that will lead to a word scramble. The word scramble isn’t necessary to complete but it does help keep those students that finish early busy! It is a really fun exercise!

Closing The Deal

10 minutes

Have a brief discussion on the benefits of using a calculator but also the dangers.

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

We have no assessment today but if you would like to do one, it could be to see how many students found the answer to the word scramble. This might help identify those more advanced learners that need more challenging work.