Question

a, 1+2-3-4+5+6-7-8+...+993+994-996+997+998

b,1-3+5-7+...+97-99+101

ghi rõ cách làm nha

Answer 1

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

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

=999

b)=(1-3)+(5-7)+...+(97-99)+101

=-2+(-2)+...+(-2)+101                  (50 số hạng -2)

=-2.50+101

=-100+101

=1

Answer 2

a) = (2-3-4+5) + ..... + (993 - 994 - 995 + 996)  + 997 + 998 + 1

= 998 + 997 + 1 = 1996

Answer 3

1+2-3-4+5+6-7-8+...........+993+994-996+997+998

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

=1+0+0+...........+?

=>Sai đề

b,1-3+5-7+..........+97-99+101

=(-2)+(-2)+..........+(-2)+101(50 số-2)

=(-2).50+101

=-100+101=1

Answer 4

a)

=(2-3-4+5)+.....+(993-994-995+996)+997+998+1

=998+997+1=1996