Question

Tính nhanh :

99-97+95-93+91-89+.......+7-5+3-1=?

Answer 1

=(99-97)+(95-93)+(91-89)+......+(7-5)+(3-1

=2+2+2+.....+2

=100 

Answer 2

=(99-97)+(95-93)+(91-89)+......+(7-5)+(3-1

=2+2+2+.....+2

=100