Math cards size

:right: Hi to everyone!
I think of doing math program with my 3- months daughter. I’ d like to make the cards or dowload them of half A4 format. Does anybody use doman maths cards? Do you use the size Doman prescribes? They are rather dificult to make by myself. Have anybody tried using maths cards of smaller size? Have you susceeded? Or it is a waste of time? Thanks in advance

Does anyone know a card trick involving math?
such as:

1.take a card
2.multiply by 3
3.add 6
4.multiply by 10
5.add 12
6.divide by 3
7.subtract 30
8.add suit value(clubs=6 diamonds=7 hearts=8 spades=9)

needs to have a minimum of 7 steps and different suit values
10 points will be rewarded to the most complex and/or the most steps