奧數問題!急

2002+2000-1998-1996+1994+1992-...+8-6-4+2

= (2002 - 6) + (2000 - 4) + (-1998 + 2) + (-1996 + 0)
+ (1994 - 14) + (1992 - 12) + (-1990 + 10) + (-1988 + 8)
+ (1986 - 22) + (1984 - 20) + (-1982 + 18) + (-1980 - 16)
+ ...
+ (418 - 390) + (416 - 388) + (-414 + 386) + (-412 + 384)
+ (410 - 398) + (408 - 396) + (-406 + 394) + (-404 + 392)
+ (402 - 400)

= 1996 + 1996 - 1996 - 1996
+ 1980 + 1980 - 1980 - 1980
+ 1964 + 1964 - 1964 - 1964
+...
+ 28 + 28 - 28 - 28
+ 12 + 12 - 12 - 12
+ 2

= 2

　2002 + 2000 - 1998 - 1996 + 1994 + 1992 - ... + 8 - 6 - 4 + 2
= 2002 + (2000 - 1998 - 1996 + 1994) + (1992 - 1990 - 1988 + 1986) + ...
　... + (16 - 14 - 12 + 10) + (8 - 6 - 4 + 2)
= 2002 + 0 + 0 + ... + 0 + 0
= 2002 //

( since 8 x 250 = 2000, so the parentheses are in the right position,
　括弧內第一個數是八的倍數e.g. 8, 16...1992, 2000, 所以括弧位置正確 )

2002-1998+2000-1996............
姐每個+4
姐4* (因為係雙so要/2,再+上2個為1次so再/2)不過最後有+2
姐4*(2002/4)+2
應該係.....
唔係教番我
小4學左唔記得

2 ( (1001 + 1000 -999 - 998 + 997 + 996 ........................+ 4 - 3 - 2) + 1)

每四個數出的結果是 4
每四個數一組共有 (1002 - 2) / 4 = 250組
2(250 x 4 + 1)
2 x 1001
2002