13 pages.
Help your students learn to count to 100 by filling in the missing numbers each month.

As the month's progress, more spaces are left open and the grids get more challenging.  This makes a great fill in for when children are done with regular work or a nice skill sheet for a substitute to plug in.  There's a blank grid that's perfect for your 100 Day celebration or to use as an assessment to see where your students are at.