iPad Screenshots


Help Xyla and Yabu trade gems back and forth by learning to add and subtract with number bonds. Use the relative sizes of number bond bars representing parts and wholes to develop number sense while solving word problems. Understand and become automatic at using tens, doubles, and other recurring patterns with numbers.

Each number bond is presented in the context of a problem that Xyla and Yabu pose for themselves. After mastering sums up to 20 (14 activities), kids explore similar patterns with sums up to 100 (13 activities), for 10 levels in all.

The game-like recognition format, in which kids choose the correct answer from three choices, provides immediate feedback in a non-busy environment conducive to thoughtful exploration.


•Number bonds present addition and subtraction facts simultaneously in terms of parts and wholes.
•Sizes of bars in number bonds show the relative sizes of quantities.
•Story format with characters Xyla and Yabu provides context for word problems.
•Activities increase in difficulty, starting with sums up to 5 and gradually increasing to sums up to 100.
•Patterns include: Counting On (+1 and +2), Doubles, Doubles +1, Making Tens, and Using Tens to make larger sums.
•Missing number activities, most with picture or bar hints, let children start forming foundations for understanding equal expressions in algebra.
•Recognition format, in which kids choose the correct answer from three choices
•Requires only single touches
•Self-contained; children will not see ads and will not have access to in-app purchases or Internet from within this app

Visit the website to download a checklist of activities and suggestions of ways to use this app in a classroom or at home.

What’s New

Version 1.2

This app has been updated by Apple to use the latest Apple signing certificate.

Updated for iOS changes; some graphic and text changes.

App Privacy

The developer, Karen McDonald, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


  • Family Sharing

    Up to six family members will be able to use this app with Family Sharing enabled.

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