Friday, December 13, 2013

Another Great Singapore Math Problem

Marilyn from NJ sent me this 4th grade problem.  First, I made a video using my smart recorder.  In my defense, I got in VERY late last night and woke up VERY early this morning, so thinking wasn't very high on my list.  This problem is a great platform for having students visualize the problem before they start to solve it.  Lots of ways to incorporate the CCS PRACTICE standards here!

Priscilla was making gift baskets. Each basket would contain three soaps and two bottles of lotion. Priscilla had 293 soaps and 167 bottles of lotion. How many gift baskets could Priscilla complete?

If I think about it, I realize I don't have to do all the division.  I can just estimate first.  I can make just under 30 baskets using the soaps and just over 80 baskets using the lotion.  Since I only want complete baskets, I need to figure out the exact number of baskets using lotion. Wish I'd thought of that before I did all this work.

This problem also highlights the issue of remainders in division.  Do I round up?  Do I discard?  Do I make it a fraction or decimal?  It makes this problem really interesting.  

All in all, a great problem.  Wish I'd thought about it before I solved it.   But isn't that what your students would do?  

Monday, December 9, 2013

Singapore Math--Model Drawing vs. Algebra

I was lucky enough to watch Kim Bell present at NCCTM a bit ago.  Kim is another wonderful SDE presenter.  She showed this wonderful comparison of model drawing to algebra.  I'm using this here with her permission.

Mrs. Grant made 300 cookies. She sold  3/4  of them and gave  1/3  of the remainder to her neighbor. How many cookies were left?

¾ * (y )+ 1/3 (1/4 * y) + x= y
Let y=300 (total cookies)
¾ * 300 + 1/3 (1/4 * 300) + x=300
225 + 1/3 (1/4*300) + x=300
225 + 1/3 (75) + x=300
225 + 25 + x=300
250-250 + x=300 – 250

Watch to video to see how much easier it is with model drawing!!