Fun with Factoring

Factoring ... fun?  Today it was!  We had a three-part math lesson on factoring and prime factorization today.  We did a great hands-on lesson from my newest math resource - Zeroing in on Number and Operations (check out the link at the bottom of my post).

We've been working on prime and composite numbers, and factors and multiples this week (I've got some FABULOUS foldables to share with you on Sunday).

Today we started with reviewing the definitions for prime and composite numbers, factors, and prime factors (we used our foldables from the week for this).  We then used the smartboard to roll the dice to form a two-digit number and list the factors for the number.

For the minds-on part of the lesson we examined the numbers and shapes I had taped to the board.  The students observed that they were all examples of prime numbers.

I then showed them a paper bag that I had written a number on (I started with 10).  I asked the students how many shapes I had in the bag if the bag had a product of 10.  Right away the students were able to answer "two shapes".  The shapes had a value of 2 and 5.  The funny thing was, even though the students were multiplying the numbers together to get 5 x 2 = 10, they kept saying "adding" instead of multiplying when justifying their answers (must FIX that immediately).  We repeated the concept for 28 and 50, which were more difficult numbers because each bag held 3 shapes (3 prime factors).  This part was done as a whole group activity.

We (I keep saying "we" because I'm part of a special PD team for three-part lessons.  Myself and another teacher (grade 2/3) team teach these lessons.  Over the course of the year we do 6 half-day lessons in my room, and 6 half-day lessons in her room) then divided the class into similar ability pairings and presented this question (and a bag with a product of 300 written on it).  Students worked together to find the answer.  Some students used a factor tree to find their answer and were finished quite quickly (I gave these students a second, much harder, number to work with if they finished quickly).  Other students worked through an "educated" guess and check strategy.  In the end, all students came to the correct answer, some just got there quicker than others.

We then grouped all the students' answers on the board for our bansho activity (to read more about the Bansho strategy, click HERE).  Basically, we had two groups for our bansho activity - students that used a factor tree to find the prime factors, and students who didn't.  While the pairs were working on their solutions, we circulate around the class recording questions we have for the students, or noting students whose strategies should be shared with the class.  Here are two examples of different strategies used by my students.  Do you see the green dots in the right hand corner of their papers?  When students finish a minds-on activity, they need to put a traffic light comprehension dot on the corner of their papers - green is for no problems, yellow is for some difficulty / questions, red is for a lot of difficulty / questions.  It's a quick and easy way to students to reflect on their work.

Students had an independent work sheet on this concept when we completed the activity (from the book at the top of the page).  They will hand in their work tomorrow (formative assessment) so I can plan from there.  But from what I saw today, I'm thinking (hoping) we'll see some great success.  I can't wait to use more activities from this book!  

Happy Thursday!!!