Mid-year multiplication and division word problems.
Thursday, December 2, 2010
I. From this week's 4th grade Investigations homework, "Multiplication Towers and Division Stories," Unit 3, Session 4.4:
People have 2 legs.
Cats have 4 legs.
Spiders have 8 legs.
1. There are 3 spiders, 2 cats, and 5 people in the house. How many legs are there altogether?
2. There are 28 legs, and they all belong to cats. How many cats are there?
3. There are 30 legs in the house. All of the legs belong to people, cats, and spiders. How many of each creature--people, cats, and spiders--might be in the house?
There are many possible answers.
How many can you find.
[Blank grid with three columns: "People," "Cats," and "Spiders"]
II. From a similar point in the 4th grade Singapore Math curriculum, Primary Mathematics 4A, "Review 3," p. 115-116:
4 people shared the cost of a stereo set and a television set equally. The television set cost $1980. The stereo set cost $1200 more than the television set. How much did each person pay?
A greengrocer had 25 crates of grapefruits. There were 38 grapefruits in each crate. He threw away 28 rotten grapefruits and sold 786 of the rest. How many grapefruits did he have left?
Lindsey bought 12 packets of orange juice. Each packet contained 375 ml of orange juice. She filled two 2-liter jugs with the orange juice. Then she poured the remaining orange juice into a tall glass. How much orange juice was there in the glass?
III. Extra Credit
1. Which problem set shows more respect for 4th graders?
2. Discuss the claim that Reform Math avoids the contrived word problems of traditional math in favor of "real world" story problems.