Comparison

ProblemSum vs Korean Flashcards TOPIK

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

ProblemSum

Practice math word problems aligned with the Singapore Mathematics syllabus for Primary 6 students. Get detailed solutions for each problem. The app works offline and requires no account.

Highlights
  • Random math word problem generation
  • Singapore Math syllabus alignment
  • Detailed step-by-step solutions
  • Offline functionality
  • No account required
  • Ad-free experience
Features
Read full description

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. Fractions, ratios, percentages, algebra, averages, rates, area and volume, 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. ROOM TO WORK IT OUT A scratch pad sits next to the question on iPad and Mac, and on an iPhone turned sideways; held upright, it slides up from below. Draw the model with a finger or Apple Pencil, or type the math. It never calculates: the first paper of Singapore's exam allows no calculator. WORKED THE WAY SINGAPORE TEACHES Tap Check Answer and the full solution opens, one tap from your own work. 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. 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. 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, and it works alongside any curriculum, at school or in a homeschool. Money is in dollars and cents, and every measure is 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. The rest is laid out the way it would be on paper: fractions stacked, ratios and money in their proper forms, and units carried through every line. WHAT IT COVERS, AND WHAT IT DOESN'T Fractions and ratios run deepest, then area and volume, percentages and whole numbers, then algebra, averages and rates, then decimals and measurement — with money, ages, time, discounts and sales tax running through them. 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. 120 cm³ or just 120. A right answer is never marked wrong for its punctuation. COME BACK TO WHAT YOU'VE DONE Recent questions stay on the device with your answers, marked right or wrong, your work and the full solution, 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. The screen rearranges itself as it changes shape — an iPhone turned sideways, an iPhone Duo opened — and nothing written is lost. With a keyboard, Command-N gives the next question and Command-Return checks your answer. WORKS ANYWHERE, TELLS NO ONE ProblemSum makes no network connections at all. No analytics, no ads, no data collection — everything is generated on the device and stays there. Spotted a mistake? Tell us at hello@problemsum.com.

About

Korean Flashcards TOPIK

Master over 5000 Korean words for the TOPIK test with this comprehensive flashcard app. It features audio for each word and is designed to provide a distraction-free learning environment for effective study.

Highlights
  • 5700 Korean words for TOPIK levels I & II
  • Audio pronunciation for each word
  • Distraction-free study environment
  • Organized by TOPIK proficiency levels
  • Designed for test preparation
Features
Read full description

Make 5,700 Korean words stick. Korean Flashcards TOPIK turns every word of TOPIK I and II into a flashcard you work through at your own pace: the word first, then a tap to reveal its romanization and meaning, then the word spoken aloud. Everything included, no ads. WHY IT WORKS Recall before reveal. The card shows the word in Hangul and nothing else. You say what it means — or admit you can't — and only then tap Reveal for the romanization and the English meaning, and Play Audio for the word in clear, standard Korean. That small effort before the answer is what makes a word stay. Back and forth through the deck with Prev and Next until a card stops needing the reveal. OVER 5,700 WORDS, TOPIK I AND II • Both TOPIK levels, each its own deck: TOPIK I (beginner) 1,846 words · TOPIK II (intermediate to advanced) 3,857 words • Hangul on the card; romanization and English meaning on reveal • Audio for every word at a tap, in clear, standard Korean • Choose how many cards per session — 10, 25, 50, 75, 100 or the whole level — a quick ten or a long sit • Prev and Next to go back over anything that didn't stick • My Stats: cards reviewed per level, with a reset for each EVERYTHING INCLUDED One price, everything open from the first launch: both levels, all 5,700 words. No in-app purchases, no subscription, no ads, no account. Works fully offline — the train, the plane, the waiting room. WHO IT'S FOR • Anyone sitting the TOPIK who wants the vocabulary automatic before test day • Learners who want to read Hangul instead of leaning on romanization • K-drama and K-pop fans who keep hearing words they almost know • Anyone who has abandoned a flashcard app out of boredom GOOD TO KNOW Complete beginner? Start with TOPIK I, ten cards a session, and tap Reveal as often as you need. Which words? The vocabulary widely studied for TOPIK I and TOPIK II — over 5,700 in all, following the study lists learners and teachers actually use. Is this a course? No. It's vocabulary, done properly. Grammar can wait until there are words to hang it on. Who makes it? A small independent studio that has been making language flashcard apps since 2016. Pick a level and see how many words stick. 화이팅!

Screenshots

ProblemSum4 screens
Korean Flashcards TOPIK4 screens

Verdict

The call

The clearest difference is price: ProblemSum at $6.99 against Korean Flashcards TOPIK's $29.99. ProblemSum also leads on update cadence (every 3 weeks vs every 10 months). Korean Flashcards TOPIK's advantage is iOS requirement (15 vs 18.0). On review sentiment, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

ProblemSum costs $6.99 and Korean Flashcards TOPIK $29.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

ProblemSum ships an update every 3 weeks, Korean Flashcards TOPIK every 10 months. The most recent releases landed on October 26, 2026 and October 27, 2026 respectively.

Scorecard3 real differences · 7 level
ProblemSum versus Korean Flashcards TOPIK: the parameters behind the verdict, then further details
ParameterProblemSumKorean Flashcards TOPIK
Price$6.99 — better$29.99
Rating5.0 (1 ratings) — better—
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings1 — better—
Update frequencyEvery 3 weeks — betterEvery 10 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, MaciPhone, iPad, iPod
Requires iOS18.015 — better
Further details — not scored
Size3 MB24 MB
Age rating4+4+
DeveloperAeterna SolutionsHandtechnics

Customer experience

ProblemSum

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Korean Flashcards TOPIK

Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

ProblemSum

No in-app purchases

None

Korean Flashcards TOPIK

No in-app purchases

Questions

Is ProblemSum free?
ProblemSum costs $6.99, with no in-app purchases.
Is Korean Flashcards TOPIK free?
Korean Flashcards TOPIK costs $29.99, with no in-app purchases.
Do ProblemSum or Korean Flashcards TOPIK have ads?
Neither ProblemSum nor Korean Flashcards TOPIK shows ads.
Which is updated more often, ProblemSum or Korean Flashcards TOPIK?
ProblemSum ships an update every 3 weeks, and Korean Flashcards TOPIK every 10 months. Most recently, ProblemSum was updated on October 26, 2026 and Korean Flashcards TOPIK on October 27, 2026.

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