Cube Counters! is a free calculator for kids. Every number is a friendly robot carrying that many counting cubes, so children can see what a number means instead of just reading it. A cheerful voice reads each number and answer out loud.
Robots leap together to add. Cubes pop away to take away. Robots line up in equal groups to multiply, and a robot bursts into equal groups to divide. Decimals are drawn at their true size, so 0.5 is half a cube.
Levels cover adding to 10, adding and taking away to 20, multiplying as groups, dividing by sharing, and missing-number puzzles like 5 + ? = 8, with hints and an optional 5-second timer. Right answers earn stars that unlock hats, robot colors and birds, and kids can design their own robot in Build a Robot.
Cube Counters! is free, with no ads, accounts or sign-up. It runs in any web browser on computers, Chromebooks and tablets, and there are free desktop apps for Windows and Mac on the download page.