Question

13 - 12 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

Answer 1

13 - 12 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=13-(12+1)-(11+2)-(10+3)-(9+4)-(8+5)+(7+6)

=13-13-13-13-13-13+13

=0+13

=13

Answer 2

=(13-12)+(11+10)-(9-8)-(7+6)+(5-4)+(3+2-1)

=1+21-1-13+1+4

=13

Answer 3

13 - 12 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=13 - (12 + 1)+(11+2)-(9+4)+(10+3)-(7+6)+(8+5)

=13-13+13-13+13-13+13

=0+0+0=13

=13

Answer 4

13 - 12 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=1 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=12 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=22 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=13 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=21 - 7 - 6 + 5 - 4 + 3 + 2 - 1

=14 - 6 + 5 - 4 + 3 + 2 - 1

=8 + 5 - 4 + 3 + 2 - 1

=13 - 4 + 3 + 2 - 1

=9 + 3 + 2 - 1

=12 + 2 - 1

=14 - 1

=13