Dino Sums is a free mathematics practice tool designed for students in Classes 1 through 5. It provides short, untimed practice sessions guided by a character named Sumi the dinosaur. The tool focuses on step by step learning: each topic begins with a worked example that shows every step, and the student then attempts a few questions with hints available one tap away. The hints reveal one step at a time and stop before revealing the final answer, ensuring the student still performs the thinking. The app is a free preview of content for these classes and is not intended as a full course or a test. Key features include a library of topics tailored to each class, such as counting, addition and subtraction within 20, making ten, two digit addition with carrying, subtraction with borrowing, times tables, halves and quarters, and money stories. The tool also offers printable PDF worksheets that are linked from each class page; each worksheet covers one topic and includes an answer key for parents. A parent summary displays the status of each topic as "Not tried," "Practising," or "Steady," allowing adults to track progress without needing to sign up or log in. The tool contains no advertisements, requires no account, and has no payment component. Typical use involves a parent or teacher setting up a learner in under a minute directly in a web browser. The student then selects a class and topic, reviews the worked example, and completes the practice questions. All practice data stays on the device, and no personal information is collected. The tool is currently available as a web application that runs in a browser, with an Android application planned for future release.