(
-2+3+4 1
+3+4+5 2
-4+5+6 3
+…+5+6+7 4
-10+11+12 9
)÷(1-11+12+13 10
+1 2
-1 3
+…+1 4
-1 9
)1 10
=(
-3×3 1
+3×4 2
-3×5 3
+…+3×6 4
-3×11 9
)÷(1-3×12 10
+1 2
-1 3
+…+1 4
-1 9
)1 10
=3×(
-3 1
+4 2
?5 3
+…+6 4
?11 9
)÷(1-12 10
+1 2
-1 3
+…+1 4
-1 9
)1 10
=3×[(1+2)-(1+
)+(1+2 2
)-(1+2 3
)+…+(1+2 4
)-(1+2 9
)]÷(1-2 10
+1 2
-1 3
+…+1 4
-1 9
)1 10
=3×(2-
+2 2
-2 3
+…+2 4
-2 9
)÷(1-2 10
+1 2
-1 3
+…+1 4
-1 9
)1 10
=3×2×(1-
+1 2
-1 3
+…+1 4
-1 9
)÷(1-1 10
+1 2
-1 3
+…+1 4
-1 9
)1 10
=6