Strategy 7: Number - Unit - Label


Teachers often report that many students simply refuse to attempt assessment items when there is a significant amount of reading, such as this item from an ACT practice test:

A hot-air balloon 70 meters above the ground is falling at a constant rate of 6 meters per second while another hot-air balloon 10 meters above the ground is rising at a constant rate of 15 meters per second. To the nearest tenth of a second, after how many seconds will the 2 balloons be the same height above the ground?

A simple strategy students can use for longer word problems such as these is to list each of the numbers in the problem, the unit for that quantity, and a label for that quantity.
number
unit
label
70
meters
height of balloon 1
6
meters per sec.
rate of falling of balloon 1
10
meters
heights of balloon 2
15
meters per sec.
rate of rising of balloon 2
1/10
second
accuracy of answer
2
balloons
I knew that already
Listing the numbers, units and labels helps students lay out the problem in pieces. In this problem, the number “1/10” gives them a clue about what they should find in the problem (see the K-W-C strategy to identify “What you want to find out.”)

The next step they choose depends on their problem-solving preference. They might make a drawing (see Strategy 9); they might make a table of values and solve it that way; they might draw a graph; they might make a single equation or a set of simultaneous equations.

To get students started on this strategy, you’ll have to talk it through with them several times (see the Think-Aloud strategy). Eventually you want them to use this kind of chart on their own to help them understand and set up the problem.