= \(\frac{1}{3}\)+ \(\frac{1}{6}\)+ \(\frac{1}{10}\)+ \(\frac{1}{15}\)
= \(\frac{10}{30}\)+ \(\frac{5}{30}\)+ \(\frac{3}{30}\)+ \(\frac{2}{30}\)= \(\frac{20}{30}\)= \(\frac{2}{3}\).(lấy mẫu chung là 30)
Học tốt !
tinh nhanh
A=\(\frac{3}{1}+\frac{3}{1+2}+\frac{3}{1+2+3}+\frac{3}{1+2+3+4}+....+\frac{3}{1+2+3+.....+100}\)
So sánh:\(\frac{\frac{\frac{1}{2}}{\frac{3}{4}}}{\frac{\frac{5}{6}}{\frac{7}{8}}}+\frac{\frac{\frac{8}{7}}{\frac{6}{5}}}{\frac{\frac{4}{3}}{\frac{2}{1}}}\) và\(\frac{\frac{\frac{1}{2}}{\frac{3}{4}}+\frac{\frac{8}{7}}{\frac{6}{5}}}{\frac{\frac{5}{6}}{\frac{7}{8}}+\frac{\frac{4}{3}}{\frac{2}{1}}}\)và \(\frac{\frac{\frac{1}{2}+\frac{8}{7}}{\frac{3}{4}+\frac{6}{5}}}{\frac{\frac{5}{6}+\frac{4}{3}}{\frac{7}{8}+\frac{2}{1}}}\)và\(\frac{\frac{\frac{1+8}{2+7}}{\frac{3+6}{4+5}}}{\frac{5+4}{\frac{6+3}{2+1}}}\)
TÍNH BẰNG CÁCH THUẬN TIỆN NHẤT
A)\(\frac{2}{3}\cdot\frac{4}{5}+\frac{1}{3}\cdot\frac{4}{5}=\)
B)\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\)
C)\(\frac{2}{3}\cdot\frac{4}{5}-\frac{1}{3}\cdot\frac{4}{5}=\)
D)\(\frac{1}{2}:\frac{3}{4}-\frac{1}{6}:\frac{3}{4}=\)
\(HELP\) \(ME\)\(!\)
1.
\(\frac{3}{4}x\frac{8}{5}:1\frac{1}{6}=\)\(2\frac{1}{3}x1\frac{1}{4}-\frac{7}{5}=\)\(4\frac{2}{3}+1\frac{1}{4}+2\frac{1}{3}+2\frac{3}{7}=\)2.
\(x.\frac{1}{2}=\frac{3}{4}+\frac{1}{5}\)\(x-\frac{1}{5}=\frac{2}{3}.\frac{9}{4}\)\(x.\frac{1}{5}+\frac{2}{3}=\frac{5}{4}\)\(\frac{13}{5}:x-\frac{1}{2}=\frac{4}{5}.\frac{15}{16}\)\(x:\frac{4}{9}+\frac{1}{3}=\frac{2}{5}.1\frac{13}{2}\)Chú ý: Dấu chấm là dấu nhân\(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}\frac{1}{1+2+3+4+5}=\)
\(\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+\frac{1}{1+2+3+4+5}=?\)
\(a,8\frac{3}{4}+4\frac{1}{5}-3\frac{3}{4}\)
\(b,3\frac{1}{2}:\frac{1}{2}+3\frac{1}{2}:\frac{1}{4}\)
\(M=\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+\frac{1}{1+2+3+4+5}=........\)
1\(M=\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+\frac{1}{1+2+3+4+5}=\)
