Day's 9 and 10 of my 30 days of creativity ( #30DoC ) involved my Kids, they are always such a massive source of ideas and creative opportunity. We have been doing numbers and basic maths recently with them, using the normal flash cards and coins. They are still not visualising numbers all that well so I decided to try and design a basic set of counters that could form games and number play before bedtime.
The main 100 grid is 150mm x 150mm so better to print in PLA than ABS, also try out the 'Brim' setting as proposed by Idolcrasher http://bit.ly/KfkAH0
And if you add a layer of a different colour on the last solid print surface the numbers will be more prominent.
More details on my Blog Here - www.richrap.blogspot.com