Nobody expects a math video to feel like a lullaby. Sansuu Chachacha takes equations that should bore you and wraps them in melodies so warm you want to live inside them. The songs stick with you longer than the solutions do, which is kind of the point. This isn't about understanding math faster. It's about discovering that learning something difficult doesn't have to feel like work. A five-year-old and a tired adult can both sit down and come away feeling lighter.

Numbers and song come together in Sansuu Chachacha, a music video that works through the solutions to a range of math problems. Rather than a regular series, it is a single musical piece made for Minna no Uta, a program on NHK. Math problems and their answers are set to music, with each solution explained in song.