Question

\(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\)

Answer 1

\(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\)

= \(\frac{2}{21}+\frac{1}{63}+\frac{1}{99}\)

= \(\frac{1}{9}+\frac{1}{99}\)

= \(\frac{11}{99}+\frac{1}{99}\)

= \(\frac{12}{99}\)

= \(\frac{2}{9}\)

Answer 2

1/3.5+1/5.7+1/7.9+1/9.11       (. là nhân bn nha)

2(1/3.5+1/5.7+1/7.9+1/9.11)

2/3.5+2/5.7+2/7.9+2/9.11

1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11

1/3-1/11

11/33-3/33

8/33

 tk nha bn

Answer 3

bằng \(\frac{4}{33}\)

nha bn