Multiplicative Inverse or Reciprocals

Today my class did a lesson with Multiplicative Inverse or Reciprocals. Hope this helps you in some way.

Lesson Introduction and Title

Their definition for the terms multiplicative inverse or reciprocal.

Example 1

 

Example 1 continued showing the reciprocal.

Showing that the reciprocal of the example is 1.

Example 2

With example 2 you have to make it an improper fraction first before doing the multiplicative inverse.

Example 2 continued with applying the reciprocal to the example.

Example 2 showing that the answer is or will be 1.

Next step in Solving Equations

Example 1

Example 1 - I teach my students way before this that variables want to be alone. I really stress the alone part by telling them a story about how the variable is always sharing his games (playstation,xbox, wii, etc.). So with equations you do the opposite and the opposite in this case is multiply the number that is with your variable. What I do to do one side I have to do to the other side. You should hear my students on this on.

Cross simplify and then multiply. The variable n is alone and equals 28.

A multiple choice question using equations.

In this example the variable has an entire fraction. To solve you do the reciprocal of the fraction to both sides. I put that in ( ).

Solving the equation and getting the multiple choice answer of d.

Math Poke a Fact

In this day and age where budgets have been cut and you as a teacher are being asked to use less paper and worksheets. Here is a way to practice math without a worksheet.  If you haven't joined "The Organized Classroom," you should. She has videos and  lots of freebies.  She is great!  I took one of her ideas and adopted it for my students. I put problems to practice Integers in place of the multiplication problems.  I didn't want to do a worksheet and yes it takes a little bit of time to make them, laminate them, and hole punch them, but after they are done, you don't have to do them again, unless you  become addicted and have to have them to practice other things in math. 

Addition of Integers-

I personally print them on neon card stock.  Then I use a cutting board to cut them the same size.  I put the answers on the back and then laminate.  I'm a little crazy when it comes to certain things and I had to hole punch them before putting the answers on the back and then hole punch them again after laminating. I know I added more work for myself, but it is just how I did them.

Students work with a partner.  One student puts the pencil in a hole, says the problem out loud, and the other student knows the answer by reading the back of the card that is facing them. Students got the necessary practice without doing a worksheet.  As the teacher, I could facilitate and I could walk around and observe the students practicing and very quickly see who was having trouble and who wasn't. 


I will be adding subtraction and multiplication in the next few days, so, please come back and get those as well. 

Hope they are something you can use. Let me know what you think?

Stacks

I'm teaching PF (prime factorization) GCF (greatest common factor), and LCM (least common multiple).  I haven't always taught them together, but the last few years I have.  It is a lot of vocabulary for the kids to learn, review, and master, but I really feel it works well together.



I teach with something that I learned about 4 years ago- stacks,  Danica McKellar talks about it in her book, Math Doesn't Suck.

Stacks are math done with an upside down division symbol, sometimes called upside down birthday cake, and anything else that someone names it.  I don't know if it really has a specific name. I found this "Youtube Video" that calls the Indian Method. She makes a straight line where I would make an upside-down division symbol.  In her video which does three numbers, which before today I had not seen and now I love it. Check the video out.

http://www.youtube.com/watch?v=WUS5bUgNm0g&feature=fvsr



I love them!  I teach students first by doing factor trees. What do you do?  What is your favorite?