Math with our Calendar

We have been using our calendar for more than just knowing the month, day, year, and day of the week.  Each week, one student is selected as the calendar helper.  They search through an array of numbers to find just the right one that comes next.  Then as a class we count how many green numbers we have, and how many blue numbers.  We are also discussing addition and subtraction to see how many more (addition) or how many less (subtraction) we see.

How many green numbers are on the calendar?  How many blue?  Which color has the most?  How many more numbers are green than blue?