Logic Grid Puzzles: Three Clues, One Answer

Two puzzles share this second-grade page, and each has the same parts: three numbered clues on the left, a three-by-three grid on the right with the children's names down the side and three pets across the top, and under it a strip of three answer boxes, one per child, each showing all three pictures. On this print the first puzzle has Ben, Mia and Tom with a mouse, a cat and a dog, and clues such as Tom does not have the mouse, with the animal drawn in place of its name. The child reads a clue, crosses out the cell it rules out, ticks a cell once it is the only one left in its row, and finally circles each child's pet in the strip.

This is the elimination puzzle in its simplest honest form: three negative clues, three children, one answer each, and every clue needed. A cross is a fact the child has established, a tick is a conclusion drawn from two crosses, and the grid makes the reasoning visible on paper so a wrong answer can be traced back to the clue that caused it. The pictures in the clues, in place of nouns, keep the reading load low for a second grader. The teacher watches for the tick that follows two crosses in a row, and for the cross that a tick forces in the rest of its column.

One portrait sheet, color helpful for the pictures. The legend of tick, cross and a filled row sits at the top right as a reminder. Work the first puzzle together and leave the second to the child. The five faces of this family each change one thing: the clue kinds, the grid size, picture clues instead of sentences, two attributes per child, or a grid already solved to read. Sudoku, with its rows and columns and no clues, is a different family.