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  • Division of Fractions Explanation

    Posted by Shelly Roberts on November 11, 2019 at 8:09 am

    I need some help with division of fractions. So we have been modelling that 3 divided by 1/2 would equal 6 because you would have 6 groups of 1/2. Now I need help explaining why when you would divide 2 1/2 by 1/3 you end up with 15/2 or 7 1/2. I get where the 15 comes from because when you take 5 one-half pieces and break those one-half pieces into thirds, you would have 15 one-third pieces, but why then do you put them into groups of 2? Or if you divide 2 1/2 by 2/3, why do you put them into groups of 4?

    Ryan Foley replied 2 years, 10 months ago 3 Members · 4 Replies
  • 4 Replies
  • Kyle Pearce

    Administrator
    November 18, 2019 at 10:09 pm

    Hi @shellyroberts

    This is a great discussion!

    First off, have you explored anything around the two types of division?

    I can’t wait to dig into this deeper with you and the community!

    • This reply was modified 3 years ago by  Kyle Pearce.
  • Ryan Foley

    Member
    February 4, 2020 at 11:53 pm

    This is a tape diagram of that problem. As a visual learner, this helps me understand. You can see the 7 groups of 1/3 and the half of a group left over. Thus 7 1/2

    • Kyle Pearce

      Administrator
      February 5, 2020 at 9:39 pm

      @Ryan-Foley

      This is super helpful.

      I agree that using concrete and visual models is so important to make sense of mathematics.

      It looks like you’ve attacked this “naked” division of fractions problem quotatively (i.e.: determining how many groups of 1/3 are in 2 1/3)

      I wonder if anyone out there is interested in trying to tackle this partitively?

      The two types of division are shared here: http://mathisvisual.com/division/

      • This reply was modified 2 years, 10 months ago by  Kyle Pearce.
  • Ryan Foley

    Member
    February 5, 2020 at 10:38 pm

    I took a stab at using partitive division (how much is in each group). It was more challenging for me to think of it this way. I wonder if that is the case for most of us or our students? It wasn’t until recently, I had even thought about division as two different questions. Here’s my attempt….