Puzzle
CubeCombo's stated finish is one remaining block, so a higher looking number is only part of the planning picture.
Read the end condition literally
CubeCombo asks you to move numbered blocks and merge matching blocks until only one remains. That gives you two things to track: the numbers that can match and the number of separate pieces still on the board. A move can look productive because it creates a prominent new number, but the useful question is whether the remaining arrangement still offers a path toward the single block objective.
Inspect the partner that remains available
Before merging a pair, look at the blocks that will stay separate afterward. Which ones could still match under the game's actual rules? Do not assume a familiar doubling sequence or movement pattern unless the tutorial confirms it. The stored description does not explain the full arithmetic or sliding behavior. Establish those details from the loaded puzzle, then use them to reason about the pieces left behind by a combination.
Recount after the board changes
Following a merge, identify the current matching relationships again rather than continuing from the old arrangement. A formerly useful partner may have changed, and a newly created block may now be the one that needs attention. Keep the final condition in view: one block, not simply the largest number you have seen. That distinction helps turn each combination into part of a completion plan instead of an isolated reward for merging something whenever possible.