ProblemSum
Word problems, Singapore-style
$6.99
New: solutions open with the strategy Singapore students are taught — draw a model, before and after, work backward. Plus more algebra and more averages.
Unlimited Singapore-style math word problems, every one worked step by step. Written for the exam that ends elementary school in Singapore — and for any child of 10 to 13 who wants a real challenge.
Ratios, fractions, percentages, money, algebra, averages, rates, time and more. Not geometry from a figure, charts or patterns drawn as shapes — those are read off a picture, and this app writes word problems.
No account. No subscription. No internet connection. Pay once and it's yours.
NOT A WORKBOOK THAT RUNS OUT
Most practice apps ship a fixed set of questions: work through them twice and your child is remembering answers instead of solving problems. ProblemSum has no such list. Every question is written the moment you ask for it, with its own names and numbers, and the solution follows those numbers — so there is no last page to reach.
WORKED THE WAY SINGAPORE TEACHES
Type an answer, tap Check Answer, and the full solution opens below. Most solutions start by naming the strategy Singapore students learn for that kind of problem — draw a model, before and after, work backward, make a supposition, guess and check — then show every line, with a check at the end that the numbers add up. Most questions also show a second way to solve it; the rest point out the trap the question sets.
WHY SINGAPORE
In TIMSS, the international math study, Singapore's 4th graders came first in 2015, 2019 and 2023. In the OECD's PISA, taken by 15-year-olds, it has finished first or second in math in every round since 2009. Its methods — above all the bar model — are now used in classrooms and homeschools across the US. ProblemSum brings them home: problems like the ones Singapore's 12-year-olds meet in their last year of elementary school, solved the way their teachers show them.
WHO IT'S FOR
The questions are set at the level of that exam, Singapore's PSLE. That suits strong 5th graders and most 6th and 7th graders — roughly ages 10 to 13 — and it works alongside any curriculum, at school or in a homeschool. Money is in dollars and cents; lengths, weights and volumes are metric.
BAR MODELS, DRAWN PROPERLY
Bars are drawn to scale with their units marked, the part that changes shaded, and brackets showing what's left — drawn for the numbers in front of you. The rest of the working is laid out the way it would be on paper: fractions stacked, ratios, percentages and money in their proper forms, and units carried through every line.
WHAT IT COVERS, AND WHAT IT DOESN'T
Ratios and fractions run deepest, then percentages, money, averages and algebra, then volume, then rates, work problems and whole numbers, with ages, area and perimeter, circles, factors and multiples, mass, measurement, number patterns and time each covered by their own kind of question. Discounts, sales tax and interest are in there too.
What it doesn't do: geometry from a figure, charts and graphs, or patterns drawn as shapes. Those are read off a diagram rather than a paragraph, so a word-problem generator can't write them. The Info tab lists both sides of that line.
ANSWER IT THE WAY YOU THINK OF IT
$4.50 or 4.50. Three-quarters as 3/4 or 0.75. A time as 1:45 p.m., 1.45 p.m. or 1345. A ratio with or without spaces. A right answer is never marked wrong for its punctuation.
COME BACK TO WHAT YOU'VE DONE
Recent questions stay on the device with their full solutions, and you can step through them one by one.
ONE APP, EVERY LEARNER
A profile for each child, each keeping its own score, so siblings can share an iPad without sharing a total.
IPHONE, IPAD AND MAC
One purchase covers all three. With a keyboard, Command-N gives you the next question and Command-Return checks your answer.
WORKS ANYWHERE, TELLS NO ONE
ProblemSum makes no network connections at all. No account, no analytics, no ads, no data collection — everything is generated on the device and stays there.
Spotted a mistake? Tell us at hello@problemsum.app.
Solutions that teach the way Singapore classrooms do, more algebra and averages, and a fresh look.
THE STRATEGY FIRST
Most solutions now open by naming the strategy Singapore students are taught for that kind of problem — draw a model, before and after, work backward, make a supposition, guess and check, make a table — and use only the words and the algebra a 12-year-old in Singapore has learned. Where a second method needed high-school algebra, it is now one a 12-year-old knows, or a warning about the trap the question sets.
MORE ALGEBRA
Expressions with a division in them, such as p ÷ 4 + 5, and equations formed from a rectangle's perimeter or from two people's ages.
MORE AVERAGES
Averages over part of a group, over groups that share a member, and as the first step of a model.
STEP THROUGH RECENTS
Up and down buttons on a recent question move to the newer or older one without going back to the list.
A FRESH LOOK
New tab icons and colors, and an app icon without the white corners that showed on the App Store and on the Mac.
AND FIXES
Corrections to the wording and working of a number of questions and solutions.
Spotted something wrong? The Info tab now says how to tell us: hello@problemsum.app.
The developer, Aeterna Solutions, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Aeterna Solutions
- Size
- 2.6 MB
- Category
- Education
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2017 - 2026 Aeterna Solutions
