Before attempting to solve the exercise, examine (possible several) model solutions in order to determine whether the B-Tree is a 2-3-tree or 2-3-4-tree, whether it employs top-down or bottom-up balancing, and whether the duplicates are inserted into the left or right branch from an equal key. After viewing the models solution, you have to reset the exercise. However, the new exercise applies the very same B-Tree than in the model solution before. Finally, insert the given keys into the initially empty B-Tree.

The keys can be inserted by drag & dropping them from the Stream of Keys into the correct positions in the tree below. Note, however, that in this exercise the keys are swapped (also "an empty key" is swapped). Thus, you can easily exchange keys with each other also inside an array or shift keys to make room for a new key. A node can be split by selecting any key in a node and pushing the Split button.