Tuesday, August 4, 2009

Math problem of the week: 3rd grade Investigations vs. Singapore Math

1. The final word problem in the 3rd grade Fair Shares Activity Booklet (TERC Investigations):

In our classroom, we have 2 bookcases. Each bookcase has 4 shelves. On each shelf, there are 10 books. How many books do we have in our classroom?

Show how you solved this problem. You can use numbers, words, or pictures.

2. The final multiplication word problem in the 3rd grade Multiplication and Division chapter of the Primary Mathematics 3A workbook:

A bicycle costs $385.A motorcycle costs 5 times as much as the bicycle.

(a) Estimate the cost of the motorcycle.

(b) Find the exact cost of the motorcycle.

3. Extra Credit

1. Investigations problems systematically require students to explain how they got their answers; Singapore problems do not. Yet Investigations, and other Reform Math programs like it, are the product of a society that prides itself on freedom and privacy. Why the uniquely American obsession with what's going on in students heads when they solve problems?

2. Have American teachers confused "explaining your answer" with "showing your work"?

3. Is it possible that sufficiently challenging problems--ones that students cannot easily do in their heads--will induce students to show their work automatically?

1 comment:

CassyT said...

It might be interesting to note that the Singapore word problem comes from the Standards Edition of Primary Mathematics, written in 2008 to California standards.

The U.S. Edition of Primary Mathematics does not introduce estimation in multiplication/division until the 4A book and contains the exact same problem without part a.