Wednesday, June 18, 2008

Math problems of the week: Grade 1 subtraction in Investigations vs. Singapore Math

My daughter just finished up a year of 1st grade Investigations, and (at home) a year of 1st grade Singapore Math.  In honor of this, let's compare how far each curriculum gets with subtraction:

I. From the final subtraction problems in 1st grade Investigations (Today's Math, p. 142; p. 153):

There are 4 butterflies on a leaf.   
Three of the butterflies fly away.
How many butterflies are on the leaf?

1. Are there more or fewer butterflies on the leaf at the end of the story?

2. How many butterflies are on the leaf at the beginning of the story?

3. How many butterflies fly away?

4. How many butterflies are left on the leaf?


There were 30 grapes in the bowl.  
Chester ate 12 of them.
How many grapes are left?


II. From the final subtraction problems of 1st grade Singapore Math (Primary Mathematics 1B, p. 180; p. 184)


(a) 39 - 28

(b) 55 - 11

(c) 49 - 28

(d) 67 - 43

(e) 75 - 30

(f) 96 - 83


Juan has 54 marbles.
He gives away 6 of them.
How many marbles does he have left?


Extra Credit (parallel to last week's assignment):

Enumerate the math skills involved in each problem.

Explain which problem set involves less hand-holding by authority figures and more student-centered discovery.

Discuss how the two problem sets reflect the cultural and political differences between American and Singaporean societies.