5×5 is the daily puzzle size. It has enough room for chains, where one tap forces another three tiles away, but it is still small enough to plan the whole board before your first tap.
Board
5×5, 25 tiles
Practice level
Medium (also the daily puzzle size)
Par
9 taps on almost every board (the daily board is usually 10)
Highest tile
5
Par figures come from solving 120 practice boards of this size with the game's solver.
Worked examples
Try each board on paper first. The solution shows how many times to tap each tile.
Example 1
11112111113142213452
Total 38 · par 9
Show the solution
×1×1×1×1×1×2×1×1
Tap each marked tile that many times, in any order
Example 2
21232223321231121121
Total 37 · par 9
Show the solution
×1×1×2×1×1×1×1×1
Tap each marked tile that many times, in any order
Tips for 5×5
The centre tile has the most neighbours. Taps there clear the most, but they also empty four tiles at once, so check you won't strand anything.
Corners of a 5×5 board often hold a 1 or 2 with an empty neighbour. Use the wall rule there first.
Practice Medium boards are the best way to warm up for the daily, since they're the same size.