In Number Merge, read the board after the move.
Learn to predict a slide, avoid double-counting merges, and keep space for the next tile.
A promising merge can still be a poor move. It may earn points while leaving the board cramped, scattering your largest tiles, or closing the route to the next useful pair. Before choosing a direction, picture the board after the slide but before the new random tile appears.
Read one line at a time
Sliding left first removes the gaps in each row. Equal adjacent numbers then merge in the direction of travel. Each resulting tile can merge only once during that move. These examples show the row before a move and the row afterward, excluding the newly spawned tile.
Slide left: 2 · 2 4 → 4 4 · · 2 2 2 2 → 4 4 · · 4 4 8 · → 8 8 · · 2 4 2 4 → 2 4 2 4
The third example does not turn directly into 16. The first two 4 tiles create a new 8, which has already used its merge for this move. On a subsequent left move, the pair of 8 tiles can combine. This distinction prevents a common planning error: expecting a whole cascade from one direction press.
Count space, not just points
A merge removes one occupied square, but a new tile appears after every changing move. If your move makes one merge, the spawn usually uses the space you just created, leaving the number of empty squares unchanged. Making two merges creates two spaces and then uses one, for a net gain of one empty square.
A slide without a merge changes positions but creates no space. If a new tile then appears, the board has one fewer empty square. Such moves can still be necessary, but you should know what rearrangement you are buying with that space.
Use a corner as an anchor
Pick a corner for the largest tile and try to build a descending sequence along its edge. If the largest tile is in the lower-left corner, a row such as 128, 64, 32, 16 gives the smaller numbers a clear direction to grow. Moving upward might pull that largest tile away and allow a small new tile to occupy its old position.
This is a practical preference, not an unbreakable rule. Sometimes the only legal move breaks the pattern. At other times, a temporary break makes a much larger merge possible. Read all four directions before deciding that the preferred corner must be protected at any cost.
Compare two candidate moves
For each candidate, ask three questions: how many merges happen, where does the largest tile finish, and what empty positions remain for the random tile? Choose the move with the more manageable resulting board, not automatically the largest immediate score. When both choices seem close, favor the one that leaves several future directions available.
Know the limit of prediction
You can predict the slide exactly. You cannot predict where the next tile will appear. In this version, a new tile is 2 with 90% probability and 4 with 10% probability. Planning should allow for more than one spawn position. A strong-looking layout is an advantage, not a promise that the round will reach 2048.