Working it out with nothing left to guess. On most of these boards the arithmetic is deliberately light, so what is left is the reasoning.
Stirring Paint has no arithmetic in it at all: a colour, a direction and a jump for every cell, until each colour closes a single loop. Hitome’s Garden turns on binary choices — every line has exactly two ways to go — which is what makes it deducible rather than merely searchable. Finding Zero and Longest Road are about using an answer you have already paid a turn for. Lozenge Land asks for the fewest blocks that let water reach every floor, and a block only stands where something holds it up. No Three in a Line asks for every line through the towers to be kept in mind at once, the slanted ones too, while the city grows. Minotaur asks for the most steps from a door to the Minotaur, where every step taken decides what the next one may be. Graceful Tree starts from the biggest difference, which only the biggest number beside 1 can make, and works down. Broken TV fills a board by one rule, so the picture a line paints can be worked out square by square, and then worked backwards to the line. Eye of Horus asks for every way to fill a circle, and the last way is easier to find knowing what can never go in: a half, since the rest of the circle would be the other half, in one run of slices side by side. Folding Polygons asks for every shape a polygon of paper can be folded into, and being sure that none is missing means keeping track of which orders of folds have been tried. Gozen, Zebra and Lonely Zebra put the same reasoning inside a game, where the other side is reasoning too. Voronoi Islands judges every turn as it ends, so a move must leave you holding half the island and should leave the other colony no move back to half. In Ariadne’s String two threads share one hall, so every step laid is also a wall the other thread has to walk round.