Principles of Mathematics – Book 1 – Additional Resources and Corrections

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This is an online webpage designed to go along with Book 1 of Principles of Mathematics.

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Helpful Resources

Note: All the links below go to external sights; we have no control over the content, nor is a listing here an endorsement. Feel free to find other online resources instead–these are just listed here as a convenience.

Online Abacus

Online Scientific Calculator

Resources for Extra Worksheets

Below are some sites that offer printable worksheets if your student needs extra practice or drill on a concept.

Percent problems:

Graphing problems:


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[1]), so the point remains.

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.”

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
The link is

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
0.42(3.14 • 2 • 3.5 cm) + 4.8 cm + 4.8 cm = 9.23 cm

Should read:
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 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
(inches instead of feet)

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
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)

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