This document contains three puzzles of increasing difficulty, all leading to the same message: "Happy 100-th day!!!".
In the first puzzle the students are asked to distinguish even and odd numbers up to 100.
The second puzzle is similar, but sometimes an addition is given instead of a number. The students need to either do the addition or remember that EVEN + EVEN = EVEN, etc...
In the third puzzle the students are asked to identify the sums that equal 100.
I have included all the answer keys in the preview file, so if you would like you can see what is in the puzzles.