## Thursday, June 2, 2011

### Math problems of the week: grade 3 Investigations vs. French Math

I. From Landmarks in the Hundreds, a student activity public for grade 3 Investigations (TERC):

Calculator Skip Counting

Choose a number to count by. Pick one you think will land exactly on 300.
Skip count by this number on your calculator.
Does it work? If so, write how many of your number it takes to get to 300.

Numbers               Did you land on         If it worked:
we tried 300         exactly?                       How many in 300
--------------------------------------------------------------------------------------------------

______________ Yes No ________________
______________ Yes No ________________
______________ Yes No ________________
______________ Yes No ________________
______________ Yes No ________________

... (18 iterations in all)

--------------

Observe:

32 x 4 = 32 x 2 x 2
32 x 4 = 64 x 2
32 x 4 = 128
32 x 40 = 1280

5 is half of 10
12 x 5 is half of 12 x 10
12 x 10 is 120
12 x 5 is 60

50 is half of 100
12 x 50 is half of 12 x 100
12 x 100 is 1200
12 x 50 is 600

43 x 2 = _____ 82 x 2 = _____ 16 x 10 = _____ 35 x 10 = _____
43 x 4 = _____ 82 x 4 = _____ 16 x 5 = _____ 35 x 5 = _____

24 x 4 = _____ 43 x 4 = _____ 23 x 5 = _____ 74 x 5 = _____
24 x 40 = _____43 x 40 = _____23 x 50 = _____74 x 50 = _____

33 x 4 = _____ 13 x 40 = _____ 26 x 5 = _____ 14 x 50 = _____
120 x 4 = _____ 21 x 40 = _____ 31 x 5 = _____ 15 x 50 = _____

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III. Extra Credit

A recent commenter on my review of Diane Ravitch's latest book writes:

We keep wondering why the USA is totally opposed to looking at successful
countries. Good old American exceptionalism concludes that right wing solutions
are required even though none of the successful nations stress testing,
privatization, teacher bashing, merit pay, or any of the other conservative
solutions.
What key factor does our commenter omit?

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Note: I've recycled this math comparison from a much earlier post. I thought now was a good time to recall that Singapore is only one of many countries whose curriculum excels over ours; it's also a good time for me, personally, as I've literally run out of time for blog-related activities this week.