Chapter 2: Approaches to Problem Solving
Assignment #1 – Unit 2A KEY
The Problem – Solving Power of Units
Pgs. 84 – 95
1. What are units? Describe how to read units that involve division, multiplication,
squares, and cubes.
The units of a quantity describe what is being measured or counted. Division is
read as “per” (miles per hour) and multiplication (120 ft2).
2. Explain why a unit conversion really involves just multiplying by 1.
Because when converting, you are multiplying by the conversion factor, ex.
1kg.
1
1kg.
3. Describe the three forms in which we can write any conversion factor. Given the
conversion in one form, such as 1 lb. = 16 oz.., how do you find the other two
forms?
1) 1 lb. = 16 oz.
2)
1lb.
1
16oz.
3)
16oz.
1
1lb.
4. Explain in words or with a picture why there are 9 square feet in 1 square yard
and 27 cubic feet in 1 cubic yard. Then describe generally how to find conversion
factors involving squares or cubes.
1yd 2  1yd .  1yd .  3 ft.  3 ft.  9 ft 2
1yd .3  1yd .  1yd .  1yd .  3 ft.  3 ft.  3 ft.  27 ft.3
General Rule: Replace 1 yd. by 3 ft. when we write out 1 square yard.
5. Describe how to read and use the currency data in Table 2.1.
Currency exchange rates change nearly every day. Dollars per foreign vs. foreign
per dollar.
6. Briefly describe how units can help you check your answers and solve problems.
Give examples.
We have covered basic ideas of units and conversions, so we are ready to apply
them to problem solving. In some cases, units can help us decide how to solve a
problem. In all cases, units offer a useful way of checking answers.
Exercises in your textbook: pgs. 96 – 99
#’s 23 – 28 ; 29 – 36 ; 37 – 46 ; 57 – 64 ; 65 – 78 ; 79 – 82 ; 83 – 86
Extra examples p. 99 #’s 88, 90, 92, 93, 94