Subtracting Sardines

App Name: Subtracting Sardines HD – Tasty Math Facts

Golden App AwardOverall Rating: 5/5

Mom’s Rating: 5/5

Kids’ Rating: 5/5

Apps for Homeschooling 5/5 ApplesRecommended Grades/Ages: Kindergarten, Grades 1-3

Skills Developed: Subtraction, Negative Numbers

Available On/Price: iPhone/iPod – $1.99, iPad – $1.99, Mac – $1.99

Reviewed on: iPad

App Description:

Subtracting Sardines is the second math app in the Tasty Math Facts series of apps to bring hands-on, conceptual learning to iDevices.  Designed much like Adding Apples (previously reviewed, 5/5 Apples), Subtracting Sardines introduces young mathematicians to a friendly penguin and his fishy food that needs to be put on ice

An icy calculator with the numbers from 1-9 and a slippery chute that the fish flip into make up the main game screen.  If you are working on a problem like 9-5, nine fish will appear when the 9 is pressed, then when the five is pressed, five of the fish will turn into bones!  When tapped to solve the bones will go poof, and the remaining fish will be encased in ice blocks.

If your child creates a problem like 1-9, one fish will appear, then when the 9 is pressed that one fish will turn into bones and eight red fish will appear (signifying a negative number of fish).  The regular set of bones will poof when touched, the red fish will turn into red bones when touched but will remain on the screen.  Alternately the = button can be pressed to automatically put the fish on ice and poof the bones instead.

When they fish are all processed a multiple choice answer screen slides out, and your child can select the correct answer.  Once the correct answer is chosen the fish and bones change to gold coins, one slips into a slot on the calculator and is added to your child’s statistics.

Correct answers, incorrect answers, and accuracy as a percent are inconspicuously displayed (those are for you Mom), while the number of coins earned, number of fish counted, and any awarded trophies are prominently displayed.  Awesome 3D penguin trophies are awarded after 25, 50, and 100 subtraction problems have been solved.

There are a number of very useful features.  You can reset the statistics, enable automatic plus button and clear button functions for small children (I like this, then your child just needs to push numbers and not the + key on the calculator), you can set the app to lock the keys that have already been used or leave them open, the music can be set on or off, and you can limit the highest number your child can use (from 2-9) so you can just focus in on lower numbers for small children and increase the level of difficulty as more numbers are learned.

You can even set up to three profiles for your children so they can earn their own trophies, you can save their own individual settings, and you can see all of their stats at a glance on the opening screen.  It’s also pretty straightforward to switch between users as well.

What We Liked:

When I heard that a subtraction app in the Tasty Math Facts series was in development, I wasn’t sure how it would handle subtraction conceptually, if it would deal with negative numbers etc.  I can’t tell you how excited I was to see how they had found a way to so naturally represent negative numbers and subtraction in general with the fish, the bones, and the red fish.  It might sound complicated in my description, but it really works, and is very simple.

I have NEVER formally taught my five-year-old subtraction, and she GETS Subtracting Sardines.  Right from her very first go at it, all the way up to nines, even the negative numbers!  She’s currently scoring 100% in this app, which blows me away.  My eight-year-old has also been a tiny bit confused about negative numbers, but the way they are just so naturally built in makes it so simple for her, it’s just amazing.  The girls actually prefer to work the reverse subtraction questions that lead to negative solutions because they like those red fish!

There is a lot of flexibility in this app; not only is it a great tool for both sit down teaching of math concepts, it’s also great fun for independent exploration and building confidence with visual representations of the problems before tackling abstract pen and paper problems.  You can focus in on specific fact families or allow a free range of play across the entire app.

Like all the apps in this series the design is top-notch and the artwork is very well-done.

What We Didn’t Like:

I asked my girls if they liked this app as much as Adding Apples, and they said it was just a smidgen less fun because the fish are harder to play with, they’re slippery fellows in their ice chute and are harder to control.  My five-year-old keeps trying to stack their ice blocks up but they always bounce away!


Subtracting Sardines is the perfect math app to introduce subtraction to young children.  It will help them build a conceptual understanding of the operation before they tackle the more abstract, numbers only math problems.  This is really ideal for beginners, those who need hands-on manipulatives, and any child struggling to understand subtraction conceptually, and it’s fun to boot!

Buy this iPad app now for $1.99!
Subtracting Sardines HD - Operatio

Also available for iPhone/iPod – $1.99 and for Mac – $1.99!

Have you downloaded this app?  Let us know what you and your children thought – leave a comment!