Các câu hỏi tương tự
Tính nhanh nếu có thể:
a)
\(\frac{1}{3}+\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}+\frac{1}{143}+\frac{1}{195}\)
b)
\(1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+\frac{1}{28}+\frac{1}{36}+\frac{1}{45}+\frac{1}{55}+\frac{1}{66}\)
Tính hợp lý;
\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+.....+\frac{1}{66}\)
Tính nhanh: N = \(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)
Tính nhanh
\(A=1+\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+\frac{1}{28}+\frac{1}{36}+\frac{1}{45}\)\(\frac{1}{45}\)
Nhanh tk !!
Tính nhanh
\(B=\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)
tính nhanh :
\(E=\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+.....+\frac{1}{120}\)
\(D=\frac{1}{1\times2\times3}+\frac{1}{2\times3\times4}+\frac{1}{4\times5\times6}+......+\frac{36}{25\times2729}\)
tính nhanh
A=\(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{5.6}\)
B=\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)
giúp mk vs
Tính nhanh :
\(\left(1-\frac{1}{3}\right).\left(1-\frac{1}{6}\right).\left(1-\frac{1}{10}\right).\left(1-\frac{1}{15}\right).\left(1-\frac{1}{21}\right).\left(1-\frac{1}{28}\right)\)
Tính nhanh:
B=\(\left(\frac{11}{4}.\frac{-5}{9}-\frac{4}{9}:\frac{4}{11}\right).\frac{8}{33}\)
C=\(\frac{1}{10}+\frac{1}{15}+\frac{1}{21}+...+\frac{1}{120}\)