Question

Tính S= 1+2-3-4+5+6-7-8+...+994-995-996+997+998.

Answer 1

S=1+2-3-4+......+993+994-995-996+997+998

=1+(2-3-4+5)+(6-7-8+9)+......+(994-995-996+997)+998

=1+0+0+......+0+998

=999

Answer 2

\(\text{ S = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... + 994 - 995 - 996 + 997 + 998}\)

\(S=1+2+5-3-4+6+9-7-8+...+994+997-995-996+998\)

\(S=1+\left(2+5-3-4\right)+\left(6+9-7-8\right)+...+\left(994+997-995-996\right)+998\)

\(S=1+0+0+...+0+998\)

\(S=1+998\)

\(S=999\)

Answer 3

S=1+2-3-4+......+993+994-995-996+997+998

=1+(2-3-4+5)+(6-7-8+9)+......+(994-995-996+997)+998

=1+0+0+......+0+998

=999

Answer 4

S=1+2-3-4+......+993+994-995-996+997+998

=1+(2-3-4+5)+(6-7-8+9)+......+(994-995-996+997)+998

=1+0+0+......+0+998

=999

Answer 5

cảm ơn các bạn đã trả lời câu hỏi giúp mình nhé....thanks nhìu...