These thematic pictures of Математика are analogous to a visual dictionary. The theme "Математика" 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 bulgarian language, which is not your native language.
To expand your bulgarian language vocabulary on the "Математика" topic, flashcards games are the best way: