Sugoku vs Answer Hider
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Sugoku
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Sugoku is a drill app for high school mathematics, shown the way it looks in a printed textbook: fractions stacked with a horizontal bar, √ with a vinculum, raised exponents, and ∫, Σ, lim rendered properly. Problems are generated on the fly, so you never run out of practice. WHAT YOU CAN PRACTICE - 235 topics covering the full Japanese high school curriculum (Math I, A, II, B, C, III): algebra and proof, quadratic functions, sets and logic, trigonometry, exponentials and logarithms, analytic geometry, differentiation and integration, sequences, statistical inference, vectors, complex plane, conic sections, limits and calculus. - Three difficulty levels, from fundamentals to university entrance exam level. - Answers are not forced to be integers: type fractions and radicals directly. The answer boxes show the shape of the answer, so you learn how results are written. - Figures label vertices, angles and side ratios; graphs plot key points (intercepts, vertex, center). - Missed problems come back immediately. Bookmarks and mistake analysis let you drill only your weak spots. KYOKUISEN (RANKING) - A daily rating match with a leaderboard grouped by school year. - One attempt per day; watch a video ad to add attempts, up to three per day. - Your nickname and rating are visible to other players. Do not enter your real name or anything you would not want public. - Offline, your own records are shown instead. SUGOKU PREMIUM (IN-APP PURCHASE) - Removes ads. - Three Kyokuisen attempts every day, no video ads needed. - Bookmarks up to 500 items (20 on the free tier). - Answer timer with time analysis, plus the Sakura skin. - One-time purchase. Restore from the settings screen. ADS - On the free tier, banner ads appear on the topic list and the result screen. - Video ads play only when you choose to add a Kyokuisen attempt. Ads never interrupt you mid-problem. PLEASE NOTE - The app interface is available in English and Japanese. Problem statements are written in Japanese; because the content is mostly mathematical notation, most problems are solvable without Japanese, but full Japanese localization of the problem text is not available yet. - Requires iOS 17.0 or later, iPhone and iPad. Study records are stored on your device. Leaderboard data is stored in Apple CloudKit. See the privacy policy for details, or contact us through the support page.
Answer Hider
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Answer Hider is a simple study app that helps you organize exam materials, hide answers in study photos, and review them before a test. Add photos of worksheets, notes, printed handouts, vocabulary lists, or problem sets. Then hide the answers or key terms you want to memorize. Tap to reveal the answer, mark it as difficult or correct, and focus your review on what you need to remember. ■ Recommended for ・Students who study from printed worksheets ・Hiding answers and reviewing them like flashcards ・Organizing range sheets and study photos separately ・Preparing for midterms, finals, and regular exams ・Studying from notes, handouts, and problem sets ・Keeping exam materials organized by subject or course ■ Main features ・Organize by exam period ・Organize by subject or course ・Separate range sheets from study photos ・Manually hide answers in photos ・Tap to reveal hidden answers ・Mark answers as difficult, correct, or removed ・Review only difficult items ・Modes for school and college use ・No ads, so you can stay focused ■ Free plan The core hide-and-review flow is available for free. The free plan includes up to 30 photos and 1 exam period. ■ Premium Premium unlocks unlimited photos and unlimited exam periods. Choose a 30-day pass, a 60-day pass, or Lifetime Pro. 30-Day and 60-Day Passes are non-renewing and do not auto-renew. Lifetime Pro is a one-time purchase. ■ Privacy This app does not show ads. It does not use external AI or automatic answer generation. Your study photos and exam materials are not uploaded to an external server. ■ Terms of Use (EULA) https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ ■ Privacy Policy https://docs.google.com/document/d/e/2PACX-1vQM37OvTcHoNAevOTIl5I1Tt3hE3vktVhNAJ63hYVhcMYRbg3_ItqM2wfe1CZg8X_xACNQheT7HYuDl/pub Study from your own photos. Hide answers, reveal them, and review what you missed.
Screenshots
Verdict
The clearest difference is ads: Answer Hider at none against Sugoku's shown. On price, in-app purchases, device support and iOS requirement 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
Both are free to download. Sugoku sells 1 one-off in-app purchase and Answer Hider sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.
| Parameter | Sugoku | Answer Hider |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 days | — |
| Ads | Yes | No — better |
| In-app purchases | Yes | Yes |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 136 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | ryo otsuka | Yuya Takamoto |
In-app purchases
Sugoku
- プレミアムプラン$1.99
Answer Hider
- 30-Day Pass$1.99
- 60-Day Pass$3.99
- Lifetime Pro$11.99





