Problema Solution
Evaluate: 1-2+3-4+............-98+99
Answer provided by our tutors
1-2+3-4+............-98+99 =
= (1 + 3 + 5 + ... + 99) - (2 + 4 + 6 + ...+ 98) =
= ((99 + 1) * 25) – (100*24 + 50) =
= 50
Evaluate: 1-2+3-4+............-98+99
1-2+3-4+............-98+99 =
= (1 + 3 + 5 + ... + 99) - (2 + 4 + 6 + ...+ 98) =
= ((99 + 1) * 25) – (100*24 + 50) =
= 50