Announcement

Collapse
No announcement yet.

R&S Math 5 Borrowing Fractions from whole numbers. lesson 76

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    R&S Math 5 Borrowing Fractions from whole numbers. lesson 76

    Why does R&S teach you to only borrow 1 from the whole number, instead of just converting it to an improper fraction? I'm looking at lesson 76. So the problem is you made 2 pies and you ate 3/4 of the 2 pies. How much is left? If I did not have this book I would have taught to just convert 2 to 8/4 and then subtract 3/4. Why do they instead have you "borrow" one whole pie and make it 1 and 4/4 - 3/4? Pictorially, I get it....but it still doesn't make mathematic sense to me (or my daughter). My daughter is very frustrated with the R&S way, but I'm wondering if this isn't a stair step way to what we want to do? What is the reasoning behind doing it this way first?
    Christine

    (2021/2022)
    DD1 8/23/09 - Mix of MP5 and MP6 (SFL, Birds, R&S 6 Math, Language Arts with Grandma)
    DS2 9/1/11 - MP4M
    DD3 2/9/13 -MP2/MP3

    Previous Years
    DD 1 (MPK, SC2 (with AAR), SC3, SC4, SC 5/6, MP4 + FFL and R&S Math 5, MPOA Fable
    DS2 (SCB, SCC, MPK, SC2/AAR/Storytime Treasures), Traditional Spelling 1, SC5/6 Year 1
    DD3 (SCA, SCB, Jr. K workbooks, soaking up from the others, MPK, AAR), MP1

    #2
    All I can say is that I have also inserted some of my own processes for solving math equations. For instance, when R&S Ar4 teaches how to take one third of 24, they pretty much say to take the denominator and divide the number by it. I taught my 4th grader that all numbers (n) are equal to n over 1 (n/1), and that you multiply across 1/3 by 24/1, then solve the division problem the fraction makes (24/3=8). Honestly, my student has not fully memorized these procedures, so she just does what the book says. I don't know if the book is waiting on some developmental milestone for abstract thinking, but it does seem to wait on some fraction procedures and teach workarounds. We did the first 3 year's worth of Shiller Math, a Montessori approach to math, and Mr. Shiller didn't believe children should conceptually be taught fractions until 3rd grade. He said they can memorize many things before then, but understanding wouldn't come until 8/9 anyway. It's an interesting idea...and R&S is pretty light on fractions until 3rd.

    I also thought the way they taught rounding (visually, on a number line) was strange, so I taught my student to underline the place value you're rounding to, look to the right, say the rule, and bump up or keep the underlined digit and replace numbers to the right with zeros. But I "get" how the visual explanation is helpful for those who would forget those "procedures." It's the same with converting units of measure. An older student could convert mixed hours and minutes to all of one unit, perform a function, and convert it back to mixed units by division, but they teach holding "sets" of unit conversions in your head to subtract from one side and add to another. Because the long division skills and casting off zeros haven't been perfected, it is a novel way to get to the right answer without having the advanced skills. I don't disagree with that process; it's just new to me.

    If you assign most work independently, I see the frustration, but honestly, you can teach her to solve it however you want. I love the VideoText guy. He spends a lot of time advocating that if students can explain how they got the right answer (and it works mathematically), then it is valid.
    Mama to 2

    Spring start MP1
    Summer start 5A

    Completed MPK, MP1 Math & Enrichment, MP2, 3A, 4A, SC B, SC C,
    SC1 (Phonics/Math), SC2's Writing Book 1

    Comment


      #3
      The stair stepping to long division I thought was really quite helpful (not they way I would have taught it, but was very helpful), so I just want to make sure I don't jump the gun here with the fractions. But, she basically solved the problem in her head (converting the number 2 to 8/4), before we read how to do it. I do assign independent work, but only on concepts previously taught.
      Christine

      (2021/2022)
      DD1 8/23/09 - Mix of MP5 and MP6 (SFL, Birds, R&S 6 Math, Language Arts with Grandma)
      DS2 9/1/11 - MP4M
      DD3 2/9/13 -MP2/MP3

      Previous Years
      DD 1 (MPK, SC2 (with AAR), SC3, SC4, SC 5/6, MP4 + FFL and R&S Math 5, MPOA Fable
      DS2 (SCB, SCC, MPK, SC2/AAR/Storytime Treasures), Traditional Spelling 1, SC5/6 Year 1
      DD3 (SCA, SCB, Jr. K workbooks, soaking up from the others, MPK, AAR), MP1

      Comment

      Working...
      X