ShowMath
Learn mental-math tricks worth showing off — then actually perform them. Name the weekday of any birthday, reveal a hidden digit, square numbers in your head. A fresh calendar puzzle every day. On-device, nothing leaves your phone.
▶ Play it nowBuilt for sittings of about 20 minutes on the screen. That is our design budget, not a measurement.
Meet your mentor
Every Spark & Anvil app has a friendly mentor character that demonstrates, asks, and patiently scaffolds learning.
Mentored by Marlow
#7c3aed Characters who teach
Meet the cast
ShowMath's Stage Crew each embody one self-working mental-math routine through a recurring defining act — the character IS the method. Surfaced at session boundaries (rehearse, then perform); Stage Manager Marlow coaches rehearse-then-perform and reveal-the-secret, and never performs for the kid.
Wendel
The Calendar-Keeper — anchors the year's doomsday and steps by sevens to name the weekday of any date
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Elvi
The Eleven-Splitter — pries a number's digits apart and drops their sum into the gap (times-eleven shortcut)
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Fiva
The Fives-Finisher — rounds a number ending in 5 to a friendly pair, then tacks on 25 to square it
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Missa
The Missing-Digit Diviner — sums the shown digits and reads the hidden one as the shortfall to the next nine (casting out nines)
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Squarl
The Squaring-Bouncer — bounces to the nearest round number and back to square any number in her head
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Dashel
The Left-to-Right Racer — answers biggest-place-first, out loud, before the calculator finishes
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Magda
The Magic-Square Weaver — seeds a four-by-four square from a date so every row, column, and diagonal sums the same
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Nabo
The 1089 Conjurer — reverses, subtracts, reverses, adds, and always lands on 1089
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Halvra
The Double-and-Halver — doubles one factor and halves the other until multiplying is easy
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Modo
The Clock-Winder — wraps numbers around a clock of any size, the engine under the calendar and missing-digit tricks
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Marlow
The Stage Manager — a warm, attentive adult who coaches rehearse-then-perform and reveal-the-secret, and never performs for the kid
Read chapter →
Browse all chapters → · What's distributed-narrative methodology? →
What's inside
Learning goal
Learn mental-math tricks worth showing off — then actually perform them. Name the weekday of any birthday, reveal a hidden digit, square numbers in your head. A fresh calendar puzzle every day. On-device, nothing leaves your phone.
Mentored by Marlow — no data leaves the device.
How ShowMath handles your kid's data
- ✅ All progress, settings, and AI-generated content stays on the device
- ✅ No analytics, no tracking, no third-party SDKs
- ✅ Free — no ads, no in-app purchases
- ✅ No personal information collected from children — in line with COPPA (updated by the 2026 FTC amendments)
- ✅ No chat with strangers — play-together rooms use a short code and preset emotes, never typed messages
ShowMath runs on ForgeKit — the open-source Swift Package Manager framework that powers every Spark & Anvil app. ForgeKit ensures consistent accessibility, COPPA compliance, and design language across the portfolio, so your kid's progress and preferences feel coherent across every app they touch.
Coming to the App Store
ShowMath is in active development. Email us to hear when it ships — no marketing, no spam, just a one-shot launch announcement.
Email me at launch