Two stone platforms float over a chasm. Build the bridge: use left −/+ to set the left part and right −/+ to set the right part (you can also drag on each side). The bridge connects when the two parts add up to exactly span the gap. Then press Check
3D math game · Best for grades 1-2
Number Bond Splitter presents two floating platforms over a chasm. Students adjust the left and right numbers until they sum to the whole, watching a crystal bridge materialise when the parts are correct. The bridge-over-a-gap metaphor makes part-part-whole relationships tangible at the earliest grade levels.
Number bonds build automatic decomposition fluency for small numbers (1–20), which is the foundation for mental addition and subtraction. Knowing that 7 splits into 3+4 or 5+2 allows students to add across ten without counting on fingers.
For the whole 8, a student sets the left part to 5; the right part automatically shows 3. The bridge appears, confirming 5+3=8. Trying 6 and then 2 shows a different valid split, reinforcing that a number has multiple decompositions.
Young students often fix one part at 1 and count up the other, missing that there are many valid pairs. The interactive drag encourages exploring the whole range of splits rather than stopping at the first correct answer.
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.