Quick estimation game — dots flash briefly, then guess how many you saw. Train your subitizing skill.
Dots flash on the screen for a brief moment.
Four answer choices appear. Tap the one that matches the number of dots you saw.
A correct guess advances to the next round. The dot count is picked at random around a target that rises by two each round (about a quarter either way, levelling off just under 50), and the four choices are always evenly spaced with the answer in a random slot, so the numbers alone never give it away. The flash starts at 420 ms and loses 12 ms per round up to round 20 (192 ms); after that it shrinks by 5% every round with no floor — under 80 ms by round 38 and under 50 ms by round 47. One wrong answer ends the game.
Goal: longest streak.
The skill this trains is called subitizing — instantly knowing a small quantity without counting. Nobody can count twenty dots in half a second, so do not try. Instead, break the flash into small clusters your eye grabs at once (groups of three, four, five) and add those handfuls together: two clumps of four and a stray is "nine".
Because the flash gets shorter and the dots more numerous each round, train yourself to read the overall density and spread rather than chase individual dots. With the four choices given, you rarely need the exact figure — just enough confidence to rule out the clearly-too-few and clearly-too-many options. Trust the snap impression your eyes form in the first instant; second-guessing usually drags you toward a wrong neighbour number.