Question

2+4+6+....+100

Answer 1

2+4+6+..........+100

=(2+100)+(4+98)+.........+(50+52)

=102+102+.......+102(có 25 số 102)

=102 x 25

=2550

Answer 2

2+4+6+.....+100=  (100+2)*((100-2)/2+1)/2=2550

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