1995 - 1 + 2 - 3 + 4 - 5 +...+ 1948 - 1949 =...

1995 - 1 + 2 - 3 + 4 - 5 +...+ 1948 - 1949 =...


1995 - 1 + 2 - 3 + 4 - 5 +...+ 1948 - 1949 = 1995 - (1 + 1949 + 3 + 1947 +...+ 975) + 2 + 1948 + 4 + 1946 +...+ 974 + 976 = 1995 - 975 × 975 + 975 × 974 = 1995 - 975 × (975 - 974) = 1995 - 975 = 1020; 그러므로 답 은: 1020.