Mental Math Shortcuts
Like Duolingo, but for Mental Math Shortcuts. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
For the part of you with thirty open tabs that never became anything.
Free forever · No credit card · iPhone & Android
Key ideas in Mental Math Shortcuts
- Rounding to the nearest ten creates numbers that end in zero
- Adding multiples of ten is faster than adding exact digits
- 19 is close to 20, 41 is close to 40, and 22 is close to 20
- Using friendly numbers to simplify mental math
- The leftmost digit represents the largest portion of the total value
- Ignoring smaller digits initially prevents mental overload
- A ballpark figure is established by the highest place value alone
- Applying the Front-End method to prioritize the most significant digits
- Rounding both numbers in the same direction compounds the estimation error
- Benchmarks like 10, 50, or 100 provide a mental 'anchor' for comparison
- Rounding one up and one down allows the 'extra' and 'missing' amounts to cancel each other out
- 50 x 10 equals 500, which is significantly smaller than 4,680
- Balancing error by rounding in opposite directions
- Multiplication is faster than repeated addition for groups of similar size
- Finding a 'middle' or typical value represents the whole group
- Using benchmarks to identify unreasonable results
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Mental Math Shortcuts the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
Why do people often prefer adding 20 + 40 + 20 over adding 19 + 41 + 22 in their heads?
Get it right to open this lesson and 10 more in the app.
Where Mental Math Shortcuts takes you
Stop reaching for your phone calculator. Learn the mental frameworks to estimate totals, calculate tips, and scale numbers instantly in your head.
- 1
Quick Wins for Daily Life
- The Power of Rounding
- The 10% Percentage Hack
- 2
Thinking in Patterns
- Breaking Numbers Apart
- Scaling and Proportions
2 sections · 4 units · 11 levels. Built to play, not to enroll.
You pick the voice
Mental Math Shortcuts is taught in the The Bestie style: your friend who just gets it. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start Mental Math Shortcuts today.
Download Tomo, search Mental Math Shortcuts, and play your first lesson in under a minute.