hiraocafe.com

What It Is

おいしい数学 is a Japanese high school math practice website with companion iOS/Android apps. Its core offering is not traditional recorded or live lessons, but a “ガチャ” random-question service that turns math problems into randomized draws. Users can randomly receive problems on topics such as integration, limits, recurrence relations, indeterminate equations, and factorization, with some services explicitly providing answers. The site also includes basic ability diagnostics for Mathematics I, A, II, and B, making it suitable for quickly checking weak areas before exams.

Core Content and Format

Based on the crawled content, the platform focuses mainly on Japanese high school mathematics and common calculation topics in university entrance exams. Difficulty is divided into beginner, intermediate, and advanced: beginner is close to textbook practice problems; intermediate corresponds to standard entrance-exam problems and students aiming for MARCH-level universities or above; advanced is aimed at students targeting highly selective universities who are strong in or interested in mathematics. Question banks such as the integration ガチャ and limits ガチャ have a very large number of possible combinations. The integration app version is marked as having 147,193,200 combinations, showing a clear advantage in the volume of randomized practice.

Pricing

Many Web services are marked as free, but some Web-based services are released on specific dates, such as indeterminate equations, recurrence relations, and limits. The mobile apps are one-time paid purchases, with prices in the text ranging from 300 yen to 1,500 yen. During the 5th anniversary campaign, the iOS integration ガチャ was reduced from 1,100 yen to 1,000 yen, the Android version from 1,000 yen to 900 yen, and the iOS integration and limits bundle from 1,800 yen to 1,500 yen. Payment methods are not specified in the text.

Pros and Cons

The advantages are its focused problem types, continuous updates, and low barrier to entry for the Web version, making it especially suitable for repeated practice to improve calculation fluency. The difficulty descriptions also help students with different academic goals choose appropriate problems. The drawbacks are that it is not a systematic course: there is no visible information on video explanations, learning paths, homework correction, progress tracking, or certificates. The instructor background only mentions an “administrator” and the possibility of in-person consultation and guidance near Shinjuku, Tokyo, with insufficient detail on specific qualifications.

Who It’s For and Access From China

It is best suited to Japanese high school students who have already studied the relevant units and need problem-drilling for consolidation, especially learners of Mathematics IIB and Mathematics III, as well as students preparing for university entrance exams. For users in China, the main barriers are the fully Japanese interface and differences in the Japanese curriculum system. The text does not provide information on access from mainland China, so this remains unknown.