A green number at the corners of the card represents a square number: the result of a number multiplied by itself (used in game 4).
A red number at the corners of the card represents a prime number:
a number that has exactly two unique divisors, 1 and itself
(used in game 5).
Multiply Symbol Appears on cards belonging to the multiplication table
(for sorting out the cards included in game 4).
“Free” Card Symbolizes a “free” card (Joker).
Monumeral © Appears on “Monumerals” (single digit numbers), i.e. numerical cards “1” to “9” (used in games 2 and 3).
Twinumeral © Appears on “Twinumerals”, i.e. numerical cards “11”, “22”, etc (used in games 2 and 3).
The “100” Card Appears only on the card “100” – “Trick or Treat?” card
(used in games 2 and 3).
Hat And the HAT? It stands for “Heads And Tails” of 6’s and 9’s.