# Corrections to Book 1 of Principles of Mathematics

While we worked hard to avoid errors, a few slipped through. Below is the corrected information for your reference.

## Student Textbook

Page 6 – General Notes to Students
Currently: “This includes writing mixed numbers as improper fractions.”
Should be: “This includes writing improper fractions as mixed numbers.”

Page 81
In the Keeping Perspective, the text should read “the associative properties of addition and multiplication.” (It currently says subtraction instead, which is incorrect.)

Page 193
In the example, 1/2 • \$3.30 is currently listed as equaling \$1.15. The correct amount is \$1.65, making the approximation of 15% of \$32.50 \$4.95 rather than \$4.45.

Page 283
In the gray box at the top, the circles are crossing out the correct proportions. The first proportions on the page are the ones that should be crossed out as incorrect instead.

Page 330
Betelgeuse is roughly 650 light years away, or 3,821,350,000,000,000 miles (or 3.82135 x 10e15 miles), not 1,400 light years. However, there are stars 1,400 light years away (our own galaxy is about 100,000 light years across), so the point remains.

Page 343
Inside the rational circle, the non-integer circle should really be removed and those numbers listed up underneath rational. Non-integers are not unique to rational numbers, as irrational numbers are non-integers too–the point the figure was attempting to make is that integers are a specific type of rational number (and there are other rational numbers that are not integers but can still be expressed as a ratio of one integer to another).

Page 359
Currently: 16 fl oz = 1 quart (qt)
Should be: 16 fl oz = 1 pint (pt)

## Student Workbook/Teacher Guide

Instructions on Listing Fractional Answers (pp. 5 and 392)
Currently: “This includes writing mixed numbers as improper fractions.”
Should be: “This includes writing improper fractions as mixed numbers.”

Workhseet 6.5, Problem 2
The instructions should read “You want your finished card to be half that width and length…”

Worksheet 6.5, Problem 6a
a. 650 = 2 x 5 x 5 x 13
130 = 2 x 5 x 13
b. LCM = 2 x 5 x 5 x 13 = 650
c. 180/650 – 65/650
d. 115/650 = 23/130
e. GCF = 2 x 5 x 13 = 130

Worksheet 8.1, Problem 3
Rather than comparing the seeds in a spiral, the worksheet should more technically compare the number of spirals in each direction. The concluding paragraph would then read: “What do you notice from exploring the spirals in sunflowers? Each of the sunflowers had a different number of seeds. Yet, when we divided the number of spirals in one direction by the number of spirals in the other, we came up with approximately the same answer every time. Regardless of the number of seeds in a sunflower, the relationship, or ratio, between the two spirals did not significantly change.”

Worksheet 10.1, Problem 2
Students should graph -25%, not -0.25%.

Worksheet 14.6, Extra Credit

Worksheet 19.2, Problem 4
The instruction to “use your ruler and compass” should be “use your ruler and protractor.”

Worksheet 20.7, Problem 7a
Currently:
0.42(3.14 • 2 • 3.5 cm) + 4.8 cm + 4.8 cm = 9.23 cm

0.42(3.14 • 2 • 3.5 cm) + 9 cm + 9 cm = 27.23 cm
Note: The baseball field shown actually has a radius of 6.5 cm, so in reality the perimeter is
0.42(3.14 • 2 • 6.5 cm) + 9 cm + 9 cm = 35.14 cm
However, with the information given in the problem, the correct answer is 27.23. The picture will be adjusted in the next printing.

Page 403, Answer to Worksheet 6.3, problem 1b

The small 4 added after the cross-outs on the second fraction (12/36) should be a 1, not a 4.

Page 404, Answer to Worksheet 6.4, problem 5b

On the second fraction, there should be a small 2 crossed out in the numerator instead of a 3, and a 5 written in the denominator instead of a 1. The answer of 1/5 is correct.

Page 409, Answer to Worksheet 9.3, problem 2b
Currently: My rate was 12.5%.

Should be: My rate was 12%.

Page 421, Answer to Worksheet 15.3, problem 1a
Currently: 7 ft(7 ft) = 49 sq ft

Should be: 7 in(7 in) = 49 sq in

Page 422, Answer to Worksheet 16.4, problem 6a

The answer should then show the conversion of inches into feet.

450 in x 1 ft/12 in = 37.5 ft

Page 447
Currently:
10 decameters / 1,000 meters = 1 hectometer (hm)
10 hectometers = 1 kilometer (km)

Should be:
10 decameters = 1 hectometer (hm)
10 hectometers / 1,000 meters = 1 kilometer (km)