Can you indicate some cases where you faced difficulties in deciding which to use? Thing has to do with the gender of nouns: we say 'Muchas gracias' because 'gracia' es feminine, while we say 'Muchos abrazos' because 'abrazo' is masculine.
– fedorquiDec 23 '19 at 09:18
@Ronnie As fedorqui explains in their comment, whether you use ‘muchas’ or ‘muchos’ depends on the gender of the noun you’re talking about. ‘Flores’ and ‘competencias’ are both feminine plural, therefore you’d use ‘muchas’. ‘Animales’ is masculine plural, therefore you’d use ‘muchos’.
– TravellerDec 23 '19 at 10:12