Singapore Math is more foundational, manipulative-based, and starts with real life in the CPA technique. It uses modeling techniques and mental math. The curriculum is difficult, without the challenging problems. It is considered rigorous, but complete.
Beast Academy is a creative problem-solving curriculum. It is a lot more visually stimulating with cartoons and uses more logic puzzles for students to learn the relationship between numbers and patterns. There are comic book characters that you follow along in a storyline, but while the math concepts are not taught in as much detail. The level of challenge is higher than that of Singapore Math and students are required to understand the math deeply, make inferences, and draw conclusions.
Beast Academy has both a paper version and a digital version. While they cover the same material, they are different and have different problems. The digital version has fill in the blank sections and will give automatic feedback, but future sections are locked until the student passes the section.
The downside with Beast academy is that it is not structured as tightly as Singapore Math is. Singapore Math builds upon previous concepts year by year in , making it easier for students to follow along year after year. It uses the same types of tools (bar modeling, number bonds) and organizational tools like tables, number lines to help students understand the concepts. The A books follow similar topics as the grade levels increase, as do the B books.
Beast Academy, while thoughtful and insightful, may result in your student having gaps because it expects students to figure things out by logically drawing conclusions. It is a good program for gifted students, while others will have to work harder to understand the concepts.