Algebra I, Geometry, Algebra II with Trigonometry, Calculus Courses (Ask Dr. Callahan)

Dr. Dale Callahan presents most of the Ask Dr. Callahan high school math classes on streamed videos accompanied by textbooks, tests and answer keys as well as course syllabi. (The exception is Algebra, which is taught by his daughter Cassidy Callahan.) Textbooks are from various authors and publishers rather than only one. Among criteria for their selection was the inclusion of many real world, practical examples and applications.

Dr. Callahan and Cassidy both teach using a whiteboard, following the lesson progression of each course textbook, but highlighting key or problematic ideas rather than teaching through the entire lesson. Students then read through the lesson and apply what they've learned by solving problems from the textbooks. This is very similar to a traditional classroom course but more efficient since students are doing more self-instruction as they read through the lessons.

Dr. Callahan is more interested in students mastering the "tools" of mathematics and understanding the principles than in having students solve the most complex and time-consuming problems. This is evident in the selection of topics covered and questions assigned.

Answer keys and/or solutions manuals are provided with each course, but not always in the same format. Interestingly, when it comes to grading student work, Dr. Callahan sets a standard of no errors. Students rework problems until they get them correct. All courses include a grading guide so you will understand how to grade student work using this system.

The videos are professionally produced and include some illustrations and occasional sound effects for "entertainment," but almost all of the presentation is direct instruction. Both Dr. Callahan and Cassidy Callahan have a casual, friendly style--not rehearsed. (Note: Dr. Callahan's occasional incorrect grammar and colloquial pronunciation might bother some parents and students.)

Dr. Callahan occasionally raises worldview issues on the DVDs, but this is not a major theme and such questions are not pursued expressing personal viewpoints. While Ask Dr. Callahan is a Christian company, all courses should be acceptable to those holding other beliefs.

Course syllabi are on the publisher's website as well as in the teacher's guide for each course. Each course purchased comes with free email support.

I received Geometry and Algebra II courses for review so my comments will be more extensive regarding those courses.


The first-year course is titled Algebra rather than Algebra I. It uses Harold Jacobs' Elementary Algebra textbook and it's companion Solutions Manual. There are about 12 hours of video presentation.


The Geometry course includes approximately 12 hours of video. The text is Geometry: Seeing, Doing, Understanding by Harold Jacobs. You will also need the companion Enhanced Teacher's Guide for Geometry: Seeing, Doing, Understanding. The complete course set comes with the above items plus the Staedtler 8 Piece Geometry Set that includes a plastic case with a compass, ruler, protractor, two triangles, automatic pencil, eraser, and spare leads.

Students will also need to use either a scientific or graphing calculator. If they intend to continue on to Algebra II, they should probably purchase a graphing calculator, but if not, a scientific calculator will do.

Tests are included within the textbook and answers/solutions are in the teacher's guide.

Algebra II with Trigonometry

This course has about 14 hours of video. The complete course includes the streamed videos, the textbook, teacher's guide, and Solutions to Selected Problems. A graphing calculator is required and will need to be purchased separately.

The text used for this course is College Algebra with Trigonometry, seventh edition, by Barnett, Ziegler, and Byleen. Textbooks sold through the publisher are all  "Used" rather than "New" since this is not the most current edition of the text. This helps keep the cost of the course lower. The publisher's website explains that the text is actually available online for free, but it's missing the answer key at the end—this is critical enough that I think you should purchase a book. Dr. Callahan does not try to cover all of the lessons in the textbook but uses only 8 of the 12 chapters. (Topics omitted include matrices and determinants, sequences and series, and some additional topics in analytic geometry. Note: Dr. Callahan skips items that are not required either as prerequisites for the next level of math or for ACT/SAT preparation since coverage of such topics is not useful for most students.) On the videos, he also tries to simplify and shorten the presentation to the most important concepts. This is all entirely appropriate since this is a college-level textbook.

The course can be divided into two parts: Algebra II or Trigonometry with a semester for each. However, the entire course is equivalent to a precalculus course. (Note: at college level, algebra II/trig and precalculus course content is almost identical. This is why a specifically labeled precalculus course is not needed in this sequence.)

The teacher's guide (a thin booklet written by Dr. Callahan) includes Dr. Callahan's course syllabus, general instructions, tests, test grade sheets, and solutions for test problems. Tests are actually a list of assigned problems from the text itself, so if a student is thoroughly understanding the assignments and working through the problems, he or she should do fine on the tests.

The Solutions to Selected Problems booklet has solutions for a limited number of the problems. The textbook includes answers to odd-numbered problems in the exercises and all problems in the reviews.


The Calculus course includes streamed videos; the textbook Calculus by James Stewart, second edition by Brooks and Cole; a teacher's guide by Dr. Callahan, Solutions Manual (companion to text). The text for this course is also a used, college-level book.

The publisher says that this course "is equivalent to Calculus I at most universities and will prepare your student to take the AP Calculus AB exam."

Pricing Information

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See the publisher's website for prices.

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Instant Key

  • Need For Parent or Teacher Instruction: minimal
  • Learning Environment: independent study
  • Grade Level: grades 9-12
  • Educational Approaches: traditional
  • Religious Perspective: secular but Christian friendly

Publisher's Info

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Disclosure of Material Connection: Some of the links in the post above are "affiliate links." This means if you click on the link and purchase the item, I will receive an affiliate commission. Regardless, I only recommend products or services that I believe will add value to my readers. I am disclosing this in accordance with the Federal Trade Commission's 16 CFR, Part 255 "Guidelines Concerning the Use of Endorsements and Testimonials in Advertising."