Imagine a big number square — 1 to 100 in rows of ten — cut into jigsaw pieces. Each piece keeps its shape, but most of its numbers have been rubbed out.
Use the patterns of the number square: one step right is one more, one step down is ten more. From one shown number you can fill a whole piece, square by square.
Harder levels use bigger numbers and pieces with fewer clues, and the tens square counts in tens and hundreds — great place-value practice.
Fill the missing numbers on pieces cut from a number square, using right adds 1 and down adds 10.
The full guide, with a worked example and common mistakes: How to play Hundred Square.
A square that counts in tens: right adds 10 and down adds 100, from 10 up to 1000.
No — pieces keep the same orientation as the number square.
Yes — every piece has at least one clue, so every square follows.