Hundreds Chart Puzzle Pieces: Fill In the Numbers

Six puzzle pieces sit on this 1st grade page, each in its own card, as if cut out of a hundreds chart with scissors: two 3-by-3 squares, an L, a plus sign and two T shapes. One cell on each piece is shaded and carries a printed number — 76, 62, 22, 17, 50, 89 on the sheet shown — and every other cell is empty with a dashed inner edge. The child writes every missing number by moving from the printed one: 1 more to the right, 1 less to the left, 10 more below, 10 less above. No chart is printed; the piece is all there is.

The page works because the printed number can sit anywhere on the piece — in a corner, in the middle, at the end of an arm — so the child has to move both ways from it, sometimes two steps in a row, and sometimes down first and then across. That is the mental hundreds chart the 1st grade base-ten work asks for: 10 more and 10 less found without counting, read straight off the place the number holds. A piece whose numbers cross a ten — 89 to 90, 50 to 49 — is the one to watch, since a child who writes 88 above 89 has moved sideways instead of up a row.

One sheet, pencil, some thirty numbers to write. This is the base page of the hundreds-chart-puzzles family and the plain fill-the-piece task; the where-does-the-piece-go page reverses it and asks where a fully printed piece belongs on an empty chart, and the find-the-wrong-number page prints the pieces filled with one error each. A hundreds chart on the wall is the only support the page needs.