These thematic pictures of Μαθηματικά are analogous to a visual dictionary. The theme "Μαθηματικά" splits into several parts. For children, especially toddlers from 1 to 5 years old, it is better to divide the sets of cards over several days, or even weeks, so the information is absorbed better. Especially it is true if you are using flashcards to learn the greek language, which is not your native language.
To expand your greek language vocabulary on the "Μαθηματικά" topic, flashcards games are the best way: