A study desk in warm window light: an open laptop showing the OmniTaught Mental Math Essentials course, a mug of coffee, an open notebook with a fountain pen, and reading glasses
A hand holding a phone running the OmniTaught app, at a sunlit table with a mug of coffee and a notebook
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Course

Mental Math Essentials

3 of 14 lessons complete

✓ The Easy Half of the Table
×1, ×2, ×5, ×10, and the halving secret · 5 min 100%
5 Building: ×3 and ×6
Double plus one more, then double that · 4 min
6 The Nines Trick and Stubborn Sevens
×9 and ×7 without tears · 5 min
7 Elevens, Twelves, and Squares
The last corner of the table · 4 min

Lesson 4

Doubling: ×4 and ×8

You mastered ×2 in the last lesson. ×4 and ×8 are the same move repeated: ×4 is double-double and ×8 is double-double-double.

7 × 4: double 7 is 14, double 14 is 28. Done. 6 × 8: double 6 is 12, double again 24, double again 48. Three quick doubles beat one memorized mystery. With practice the intermediate steps vanish and 7 × 4 just says 28.

Real life: Four tickets at $27 each: double to 54, double to 108. You just did 27 × 4 faster than finding your phone.

Drill it now, while it is fresh. 12 problems, no timer.

1 of 12

Type the answer

4 × 7 = ?
28

No multiple choice here. Real life does not offer four options.

The lesson on the screen is a real one

Do the math in your head
and actually remember how.

14 lessons, 180 practice questions, 57 flashcards, and 1 timed exam set. Other Math Courses.

Other Math Courses

Built the same way, and every one of them is included.

1/2Fractions & DecimalsThe bridge most of us missed, finally explained $Money MathPaychecks, interest, deals, and tips without a calculator %Statistics LiteracyRead studies, polls, and headlines without being fooled

And if the thing you need is not on the shelf at all, the Topic Genie builds a full course on anything you name, with the same lessons, questions and review schedule as this one. Beta testers get a code the day they join.

Who builds this

Built by a teacher who became a National Certified Counselor.

OmniTaught is developed by Michael C. Shedrick, M.S., PLPC, NCC: a teacher with a master's degree in educational leadership who went on to become a National Certified Counselor. Both jobs kept exposing the same problem: learning tools that stop at definitions. So this course teaches the working version of its subject, the part you actually use when the real thing is in front of you, and it teaches it the way memory works: a short lesson, a quiz while it is still fresh, and review that brings it back before you lose it.

Also from the same desk, in case they are useful: OmniPsyche Counseling Tools, which preps your next session and not just your notes; OmniPsyche.org, free mental health education with no paywall and no signup; and NOTICE, a free guided meditation app.

What this course covers

Every lesson is short enough to finish in one sitting and ends with questions that make you use what you just read. The last ones are timed, in exam conditions.

  1. You Were Never Bad at MathHow this works, and a warmup4 min
  2. Adding & Subtracting in Your HeadLeft to right, friendly tens, round and adjust5 min
  3. The Easy Half of the Table×1, ×2, ×5, ×10, and the halving secret5 min
  4. Doubling: ×4 and ×8Double once, twice, three times4 min
  5. Building: ×3 and ×6Double plus one more, then double that4 min
  6. The Nines Trick and Stubborn Sevens×9 and ×7 without tears5 min
Show all 15 lessonsShow fewer
  1. Elevens, Twelves, and SquaresThe last corner of the table4 min
  2. Division Is Multiplication BackwardsSame table, read the other way4 min
  3. Fractions and Percents Are the Same ThingThe family tree5 min
  4. The 10% and 1% Building BlocksEvery percent is built from two moves5 min
  5. Any Percent of Any NumberStack the blocks, or flip the problem5 min
  6. Tips Without a CalculatorThe restaurant superpower6 min
  7. Discounts and Sales TaxWhat you actually pay5 min
  8. Percent Change, Both DirectionsRaises, drops, and 'what percent is that?'6 min
  9. Mental Math Timed Simulation: Set A30 items, 15 minutes, exam mode15 min

A whole lesson, start to finish

Not a sample and not a summary. This is all of lesson 2, exactly as it reads in the app.

Lesson 2 of 15 · about 5 min

Adding & Subtracting in Your Head

Left to right, friendly tens, round and adjust

Strategy 1: left to right

63 + 28: tens first (60 + 20 = 80), then ones (3 + 8 = 11), so 91. Say the running total in your head, not the digits.

Strategy 2: make a friendly ten

Numbers ending in 8 or 9 are begging to be rounded. 49 + 27: treat 49 as 50, get 77, take back the 1: 76. You borrowed, so you repay.

Strategy 3: subtract by adding up

83 - 57: instead of borrowing, climb from 57. Up 3 to 60, up 23 more to 83: total climb 26. Subtraction is just measuring the gap, and climbing is easier than cutting.

Real life

This is the checkout-line skill: is $63 + $28 more than the $90 in your budget? Tens first gives you 80, the ones add 11, so 91: just over. Two seconds, and the close calls are exactly when you finish the ones.

Questions people ask

Is there an app for practicing mental math?

Yes. OmniTaught opens in any browser and installs to a phone or a computer like an app, and it works offline once you have opened it. Mental Math Essentials is 14 lessons, 180 practice questions and 57 flashcards, and the first week is free with no card.

What does Mental Math Essentials cover?

Times tables, tips, and percentages: the tricks school skipped. It is 14 lessons long, plus 1 timed exam set in exam conditions, and every lesson ends with questions on what you just read.

How long is each lesson?

About 5 minutes. There are 14 of them, so the reading comes to about 67 minutes in total, and it is built to be done a lesson at a time rather than in one sitting.

How much practice is in it?

180 practice questions, every one with an explanation of why the right answer is right, plus 57 flashcards that come back on a schedule built from how well you knew them last time.

What does it cost?

Nothing for the first week, and no card is asked for. After that OmniTaught is $9.99 a month or $79 a year, which opens every course on the site, this one included, plus one Genie course a month.

Free for a week. Then $9.99 a month.

No card to start.

EVERYTHING INCLUDED
$9.99a month, or $79 a year
  • Every course in the ever-growing library, every quiz, & your review deck.
  • One Genie course a month, built on whatever you name. Extra courses are $6.99 each. Add narration to any Genie made course for $9.99.
  • A free week first, no card needed. Cancel any time from Settings.
Start Mental Math Essentials free

Flashcard apps have the science but no content. Content sites have no retention engineering. This one has both, built one craft at a time.