Remove stones with the − / + buttons for each digit (hundreds, tens, ones), or drag down over a column to remove a stone. When a column is too small, press − to break a ten-stone from the next digit into ten little stones (the bridge breaks). Then press Check
3D math game · Best for grades 2-4
Take the stone bridge apart block by block to reach the difference, breaking a ten-stone when a column runs out
Taking apart the bridge during subtraction shows how borrowing from a higher place helps when a column is short.
The game builds understanding of Arithmetic. Remove stones with the − / + buttons for each digit (hundreds, tens, ones), or drag down over a column to remove a stone. When a column is too small, press − to break a ten-stone from the next digit into ten little stones (the bridge breaks). Then press Check
calculation, number composition, place value, and basic operations.
Students see the quantity, adjust it directly, and check the result immediately.
This builds number sense instead of relying only on memorized answers.
Use it for individual practice, paired work, or a short class demonstration before worksheets.
Start with the game above, then continue with written practice to reinforce the skill.