I ALSO DISCOVERED you need to make the pencil lines faint or they show through the washi tape!
Once I had the grid up, I stuck squares of velcro in each space (still need to do for the days of the week at the top of the grid!) and their corresponding other side to the back of the number cards. Note: my calendar starts with lunes, as many do in Spanish speaking countries- add culture wherever you can!) Now, I can change out the numbers easily each month or have the kiddos put them on. Love it!
ALONG THE SIDE, I put the months, also with velcro, as well as the month at the top- again, will be easy to change out each month. I still need to add the year, and cards for 'Hoy es ____', 'Ayer fue ____' and 'Mañana será ____' and then it will be perfect!
IF YOU LIKE THE CALENDAR SET you see in the pictures, you can purchase it as a printable download in our store here.