claim: Your odds of correctly guessing the outcome of a flipped coin are 1 in 2, but your odds of guessing correctly twice in a row are only 1 in 4 —
evidence: P (  A  or  B  ) = P (  A ∪ B  ) = P (  A  ) + P (  B  ) − P (  A ∩ B  ) = P (  A  ) + P (  B  ) − 0 = P (  A  ) + P (  B  ) { \displaystyle P( A{ \mbox{  or  } }B )=P( A\cup B )=P( A )+P( B )-P( A\cap B )=P( A )+P( B )-0=P( A )+P( B ) } For example, the chance of rolling a 1 or 2 on a six-sided die is P (  1  or  2  ) = P (  1  ) + P (  2  ) = 1 6 + 1 6 = 1 3 .