Buildbox template, that can be used to publish to iOS, Android,  Amazon, and Windows markets.

The App:

If you want to improve your math skills, this is the right app for you. The goal of the app is to enrich and improve your knowledge of middle-school math topics. Nonetheless, this app is suited for all ages as it covers a variety of topics with examples and contains no ads or in-app purchases.
Topics are purposely kept short so that you can study for just 10 minutes a day but still be ready for school. Since the app also works offline, you can always sneak in a quick read or recap on your way to school or work. The topics are presented in four units as follows:
Equations, Multiplication Table, Division, Fractions, Equations, Decimals, Expressions, Percent, Area, Volume, Perimeter, Surface Area, Geometry, LCM-GCF, Mean, Median, Mode, BEDMAS/PEMDAS, Conversions, Exponents, Pi, Ratios, Math Symbols

Enjoy!

App Features:

Works offline
Practice flashcards
Tips
Tricks
Variety of topics

Requirements:

Buildbox 3
Android studio for Google Play
XCode for App Store
Any image editing software

Instructions:

Buildbox 3 manual- https://www.buildbox.com/help/...
Buildbox 3 Learning Center at: https://www.buildbox.com/tutor...

Buildbox:
Open the Zip file
Open the .bbdoc file
Using the File/Project Setting option replace app icon, package name
Replace the game's images with your images matching the dimensions
Change the necessary information in project Setting with your own. Especially the game name and the bundle ID.
Using File/Export option export the app for iOS, Android, Windows file for store submissions

Google play/Android Studio
Import the project into your Android studio.
Run and test the app on Android Device/Emulator.
Build .aab app bundle.
Publish app in the play store.

App Store/XCode
Import the project XCode.
Resign bundle
Run and test the app on Emulator and iOS device.
Archive the project.
Publish app in the App store