The next International Day of Mathematics on March 14, with theme « Mathematics unites »
In particular this year they are proposing proofs without words: https://www.idm314.org/resources/activities/idm-proofs-without-words-en.pdf
as one way to illustrate that there is one mathematical language for the whole planet.
Please visit the website : www.idm314.org
invitation letters in:
English: Invitation_schools English
Spanish: Invitacion_escuelas
Portuguese: Invitation_schools_Portuguese
French: invitation_écoles French