# Corrections & Clarifications for Book 2 of *Principles of Mathematics*

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

**Textbook**

p. 81: “Subtract -3/8” should read “Subtract 3/8”.

p. 42 – Prime number wording should include the word “evenly.”

*“Whole numbers that can’t be evenly divided by any whole number but themselves and 1.”*

p. 50 – On both of the maps, -160^{o} should read -150^{o}.

p. 55 – In the first example, “Remember, UTC-0:300…” should be “Remember, UTC-03:00.”

p. 259 – In the words of the example, it should say “greater than 0” rather than “greater than or equal to 0.”

Chapter 18 (Trigonometry) – *Clarification: *Should you have difficulty obtaining the correct answers on your calculator, check to make sure it is not in radian (RAD) instead of degree (DEG) mode (look for a RAD or a DEG on the screen). All of the angles in the curriculum are given in degrees, so you will need your calculator in degree (DEG) mode in order to get the correct answers.

p. 384 – So a 4% APY means that, over the course of a year, a starting balance of $1,000 [should be $10,000] will earn 0.04 • $10,000, or $400, in interest.

**Student Workbook/Teacher Guide**

**Page numbers on worksheets in Chapter 1 and 2**

*These page numbers refer to page numbers in the Teacher Guide. Should just say to “Consult the reference sheets in the back of the Teacher Guide.” *

* p. 41 (Worksheet 2.6), problem 1e*Berlin is normally 9 hours different from Los Angeles. This problem was set at a time when one is on Daylight Savings and the other is not. We’ll be changing the problem in future printings to be a different time to yield the normal time difference.

**p. 50 (Worksheet 3.4), problem 4f**

Equation should be 5 = 50/10

*Page 52 (Worksheet 3.5), problem 4, and Page 55 (Worksheet 3.7), Problem 2*

(The formula is also included on p. 431 of your reference sheets for easy reference.) SHOULD BE

(The formula is also included on your reference sheets for easy reference.)

* p. 53 (Worksheet 3.6), problem 1a*There is a “v” next to one of the numbers; just ignore it, as it should be deleted.

** p. 67 (Worksheet 5.1A), Top **See your reference sheets (p.429–430) for conversion ratios. SHOULD BE See your reference sheets for conversion ratios.

**p. 68 (Worksheet 5.1A), problem 3**

Should say 2a instead of 1a.

*p. 76 (Worksheet 5.3B), problem 3b*

Question should say “travel 15 miles” as opposed to “travel 5 miles.”

**p. 112 (Worksheet 8.3), problem 5d**

Should reference problem 5c, not 4c.

**p. 141, Worksheet 11.3, problem 1**

The points that correspond with the last 3 rows of the chart should be removed from the graphs. As it is right now, there is no work for the students to do. Parents can make up 3 additional points to have the child graph. For example, a lot size of 1, square footage of 2,000, and selling price of 200,000; a lot size of 2, square footage of 1,000, and selling price of 150,000; and a lot size of 1, square footage of 1,000, and a selling price of 100,000.

**p. 164 (Worksheet 12.6), question 5**

Questions b. and c. referring back to 4a should read to refer back to 5a.

**p. 165 (Worksheet 12.7), questions 2d-2e**

The questions should read “with *at least one gene*” instead of “with one gene.”

* p. 182 (Worksheet 14.1), question 4b*Equation should be listed as d = -50t, which corresponds with the graph and Answer Key.

* p. 188 (Worksheet 14.3), problem 2a*First row of chart should list a 1, not a 0, since the problem says that 0 < n. This will have it correspond with Answer Key.

**p. 224 (Worksheet 16.2), problem 4b**

The spelling of Jupiter should be fixed.

*p. 244 (Worksheet 17.2), problem 7a*

Here is a solution for the problem, as the 10^-5 versus 10^-4 can be confusing.

You can’t just add 4.7 and 5.2 together, as they’re being multiplied by 10 to different places. Rewriting them as decimals can make this clear.

4.7 x 10^-5 = 0.000047

5.2 x 10^-4 = 0.00052

Adding them together = 0.000567 = 5.67 x 10^-4

**p. 288 (Worksheet 20.4), problem 4b**

The reference is to 4a not 4e.

** p. 309, 311, 313, 315, 317, 319, 321, 323, 325, 335, 347, 357 **You may consult the reference sheets (p. 423–428) as needed. SHOULD BE You may consult the reference sheets as needed.

**p. 359 (Test 5), problem 4e**

Reference is to 4b not 5d.

** p. 367 (Answers for Worksheet 3.4), problem 4f**Equation should be 50/10 = 5

**p.** **369 (Answers for Worksheet 4.3, problem 2**

Answer should not say “21 is the correct value for x.” (The correct value for x is really 63, but that’s not part of the question.)

**p.** **369 (Answers for Worksheet 4.4, problem 3e**

Answer should not say “-20 is the correct value.” (The correct value for x is really 2, but that’s not part of the question.)

**p.** **370 (Answers for Worksheet 4.5, problem 2**

Answer should not say “60 1/2 is the correct value for x.” (This wasn’t part of what students were asked to write down.)

**p. 370 (Answer to Worksheet 4.5), problem 4c**

Solution should show 56 everywhere it shows 52.

**p. 371 (Answers for Worksheet 5.3A),problem 1c**

The “= 1” is missing; the first ratio should also have 231 instead of 213 in the denominator.

**p. 381 (Answers for Worksheet 10.5), problem 1d**

Answer should be x < 55^{o } F.

**p. 381 (Answers for Worksheet 10.5), problem 2d**

Answer should be x ≤ 95.

* p. 390 (Answer for Worksheet 13.5), problem 3a*Answer should be x > 0.

**p. 395 (Answer for Worksheet 14.5), problem 3e**

Answer should be deleted, as there is no problem 3e.

**p. 398 (Answers for Worksheet 15.4, problem 3a)**

The graph should look like the photo shown here.

**Answers for Worksheet 15.6, problem 3**

Answer should say where *h* ≥ 0, not *x* ≥ 0.

**p. 403 (Answer for 17.5, problem 5a)**

Answer should say 5.79065 ×10^{29}. However, the problem really should be changed to be 5.79 x 10^{25} + 6.5 x 10^{25}, in which case the answer would be that that equals 12.29 x 10^{29}, which equals 1.229 x 10^{28} when rewritten in scientific notation.

**p. 412 (Answers for Worksheet 21.3B, problem 1a)**

Graph should have an open point instead of a closed one.

**p. 413 (Answers for Quiz 1, problem 3b)**

The answer should read 8,064 *cubic* inches, not *square* inches.

**p. 414 (Answers for Quiz 4, problem 2a)**

The answer should read 120 *cubic *feet, not *square* feet.

**p. 416 (Answers for Quiz 13, problem 2a)**

The answer should be *4*, not *2.*

**p. 418 (Answers to Test 1, problem g)**

The answer key addresses the question “How many cubit feet is the cylinder portion of these 4 silos if the cylinder portion of each one has a radius of 6 ft and a height of 32 ft?”

As the question is worded currently, the answer (p. 418) should include an additional step:

*Bushels in all 4 cylinders* = 14,469.12 ft^{3} • 12 in/1 ft • 12 in/1 ft • 12 in/1 ft • 1 bushel/2,150.42 in^{3} = 11,626.86 bushels

Alternately, the question can be modified to only ask for the volume in cubic feet.

*Note:* The conversion between bushels and cubic feet is found on p. 430.

*Note: *The most recent printing incorrectly lists multiplying by 1 bushel/2,150.42 in three times. One should only multiply one time, as 1 bushel equals 2,150.42 in^{3 }, not just inches. The final step should read as follows:

*Bushels in all 4 cylinders* = 14,469.12 ft^{3} • 12 in/1 ft • 12 in/1 ft • 12 in/1 ft • 1 bushel/2,150.42 in^{3} = 11,626.86 bushels

** p. 420 (Answers for Test 5, problem 3a)**

The column in the table labeled *b* should be -600, 0, 600; the column in the table labeled *p* should be -300, 0, 300.

**Clarification on Quizzes and Tests:**

When students are told they can consult reference sheets, they are allowed to consult *any* reference sheet (see back of Teacher Guide) even if fewer page numbers are listed.