Question

Tính tổng giá trị biểu thức sau đây :

999/1000 + 998/1000 + 997/1000 + .....+ 1/1000

Làm ơn giúp mk vs

Answer 1

1/1000*(999+998+....+1)

=1/1000*((999+1)×998/2+500)

=998/2+500/1000

=499+1/2

Answer 2

 999/1000+998/1000+997/1000+...+1/1000

=(999/1000+1/1000)+(998/1000+2/1000)+...+(499/1000+501/1000)+500/1000

=(999+1/1000)+(998+2)/1000+...+(499+501/1000)+500/1000

=1000/1000+1000/1000+...+1000/1000+500/1000

=1+1+...+1+500/1000

=499+1/2

=998/2+1/2

=998+1/2

=999/2