Mystery Number: Two Arrows, One Square

Each of the eight cards on this 2nd grade page holds two shaded numbers stacked one above the other, an arrow beside each, and a single dashed box that both arrows point into. On the sheet shown the first card reads 24 with a down arrow and 33 with a right arrow: 10 more than 24 is 34, 1 more than 33 is 34, and 34 is the mystery number. The arrow key at the top — up −10, down +10, left −1, right +1 — is the only text. One clue is always a move of 10 and the other a move of 1, and the child writes the one number both clues reach.

Two arrows meeting at one square make the page self-checking, which is why it works as an independent task: if the child's two moves give two different numbers, one of them is wrong, and they know it before the teacher does. The two-clue shape also lets a child who is unsure of one move use the other — a child who cannot yet do 10 more than 24 can do 1 more than 33 and then see what 24 down must be. The cards are wordless apart from the key, so the page reads the same in any classroom.

It prints on one sheet with eight boxes to fill. This is the riddle face of the hundreds-chart-puzzles family: the jump-puzzles page chains three moves from one start instead, and the base puzzle-pieces page does the same 10-and-1 moves on a cut-out piece. Use the mystery page when children can do the moves and you want them to check their own work.