Is something broken? Need to fix it? Sounds like time to visit Digit! Fix it, Digit!

'The learning support is superb and the app feels more like a sophisticated game rather than an instructional app.' The iMums, 5 stars

Solve addition and subtraction puzzles and uncover a story about gadget fanatic Digit and his robot Bobo. Problems and story episodes unlock as learners progress through 2 structured learning pathways.

1) Fix It, Digit!
Digit must complete the electric circuit puzzles to fix the gadgets and he needs your help! These puzzles are based on the full partitioning strategy used in school. Large numbers are broken into place values (469 = 400 + 60 + 9) and then added together.

2) Digit’s Black Out!
The ship is dark, the lights went out. It's time to give Digit a shout! Digit’s robot, Bobo, gets to work joining two points on an electric number line. Kids add and subtract big numbers with small steps! These puzzles are based on a partial-partitioning number strategy. Working with a number line model enables little mathematicians to visualize the computation as they work closer and closer to the sum or the difference.

3 animated tutorials walk learners through two different methods of adding and subtracting.

This app contains puzzles for free and 1 in-app purchase to unlock all remaining puzzles.

√ Addition and subtraction within 1000 using place value
√ Designed for kids aged 6-9
√ Meets Common Core Standards
√ Boosts problem-solving and thinking skills
√ Unlock the story and problems as you progress
√ Animated tutorials
√ Hints and instructional content for each problem
√ One in-app purchase for full access to all puzzles

The learning objective of the app is for children to understand and practice general methods for adding and subtracting 3-digit numbers using place value. These electric puzzles are designed to help kids maintain and build their fluency with adding and subtracting within 1000.

Number sense and computational skills are built on a firm understanding of place value. In Electric Sums, kids demonstrate a deep understanding of place value beyond algorithms.

Electric Sums helps learners to:
- Investigate, understand and use place value to manipulate numbers
- Develop understanding of addition and subtraction
- Use strategies and properties of operations proficiently and fluently
- Relate addition and subtraction in a problem-solving context
- Represent equations with a letter or symbol standing for the unknown quantity
- Use strategies for verifying answers, evaluating the reasonableness of results

CCSS.MATH.CONTENT.3.NBT.A.2 - Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.

Lumio is a collection of kids educational apps targeting tricky math topics in fun ways.

The apps introduce learners to key concepts using concrete models and familiar but quirky contexts. Abstract ideas come to life for kids using targeted touch interactions.

Lumio apps are fully tested with parents, teachers, and kids. Find out more about our beta testing group at

What's New

Version 1.2

Minor bug fixes.

Ratings and Reviews

Mr Beckingham ,

Great app

Great app - thanks

P major ,

Creative app for learning math

I played this app with my 8 year old nephew. I didn't know there were learning apps for kids of such high quality like this one. We both enjoyed it!

Andreab415 ,

Great fun way to learn math!

My daughter is really enjoying this new app. She is learning place value and it reinforces her addition skills in a fun way. She especially likes the mad scientist character- he makes us laugh so hard! Sometimes I feel like she plays just to see what he will say next.


Lighthouse Learning Studios Ltd
26.3 MB
Requires iOS 6.0 or later. Compatible with iPhone 4, iPhone 4s, iPhone 5, iPhone 5c, iPhone 5s, iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE, iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, iPhone XS, iPhone XS Max, iPhone XR, iPad, and iPod touch.
Age Rating
Rated 4+
© Lighthouse Learning Studios Ltd 2014
In-App Purchases
  1. Full Version (full access to all content) $2.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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