Question

What is the value of 1 − ( 2 − ( 3 − ( 4 − 5 ) ) ) 1 − ( 2 − ( 3 − ( 4 − 5 ) ) )

Answer 1

51

1−2+3−4+5−.....+101

=(1+3+5+.....+101)−(2+4+6+.....+100)

=(1+3+5+.....+101)−2(1+2+3+.....+50)

=(51)

2

−2(

2

50(50+1)

)

=2601−2×1275

=2601−2550

=51