Violympic toán 6
Các câu hỏi tương tự
Tính giá trị của biểu thức:
a)\(A=\) \(\frac{\frac{1}{3}+\frac{1}{9}-\frac{1}{27}}{\frac{5}{3}+\frac{5}{9}-\frac{5}{27}}\)
b)\(B=\frac{\frac{2}{3}-\frac{1}{4}+\frac{5}{11}}{\frac{5}{12}+1-\frac{7}{11}}\)
a,left(9,75.21frac{3}{7}+frac{39}{4}.18frac{4}{7}right).frac{15}{78}
b,frac{-7}{21}+left(1+frac{1}{3}right) c,frac{2}{15}+left(frac{5}{9}+frac{-6}{9}right)
d,left(frac{-1}{5}+frac{3}{12}right)+frac{-3}{4}
e,frac{4}{20}+frac{16}{42}+frac{6}{15}+frac{-3}{5}+frac{2}{21}+frac{-10}{21}+frac{3}{20}
Đọc tiếp
\(a,\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right).\frac{15}{78}\)
\(b,\frac{-7}{21}+\left(1+\frac{1}{3}\right)\) \(c,\frac{2}{15}+\left(\frac{5}{9}+\frac{-6}{9}\right)\)
\(d,\left(\frac{-1}{5}+\frac{3}{12}\right)+\frac{-3}{4}\)
\(e,\frac{4}{20}+\frac{16}{42}+\frac{6}{15}+\frac{-3}{5}+\frac{2}{21}+\frac{-10}{21}+\frac{3}{20}\)
a,frac{16}{15}cdotfrac{-5}{14}cdotfrac{54}{24}cdotfrac{56}{21}
b,5cdotfrac{7}{5} c,frac{1}{7}cdotfrac{5}{9}+frac{5}{9}cdotfrac{1}{7}+frac{5}{9}cdotfrac{3}{7}
d,4cdot11cdotfrac{3}{4}cdotfrac{9}{121}
e,frac{3}{4}cdotfrac{16}{9}-frac{7}{5}:frac{-21}{20}
g,2frac{1}{3}-frac{1}{3}cdotleft[frac{-3}{2}+left(frac{2}{3}+0,4cdot5right)right]
Đọc tiếp
\(a,\frac{16}{15}\cdot\frac{-5}{14}\cdot\frac{54}{24}\cdot\frac{56}{21}\)
\(b,5\cdot\frac{7}{5}\) \(c,\frac{1}{7}\cdot\frac{5}{9}+\frac{5}{9}\cdot\frac{1}{7}+\frac{5}{9}\cdot\frac{3}{7}\)
\(d,4\cdot11\cdot\frac{3}{4}\cdot\frac{9}{121}\)
\(e,\frac{3}{4}\cdot\frac{16}{9}-\frac{7}{5}:\frac{-21}{20}\)
\(g,2\frac{1}{3}-\frac{1}{3}\cdot\left[\frac{-3}{2}+\left(\frac{2}{3}+0,4\cdot5\right)\right]\)
Chứng minh rằng:
1)B=\(\frac{4}{3}+\frac{10}{9}+\frac{28}{27}+...+\frac{3^{98}+1}{3^{98}}< 100\)
2)C=\(\frac{5}{5.8.11}+\frac{5}{8.11.14}+...+\frac{5}{302.305.308}\)<\(\frac{1}{48}\)
3)D=\(\frac{11}{9}+\frac{18}{16}+\frac{27}{25}+...+\frac{1766}{1764}\)
\(40\frac{20}{43}< D< 40\frac{20}{21}\)
1.tính các biểu thức sau bằng một cách hợp lí
a.frac{108}{119}.frac{107}{211}+frac{108}{119}.frac{104}{211}
b.frac{15}{19}.frac{27}{33}+frac{15}{19}.frac{19}{33}-frac{15}{19}.frac{13}{33}
c.frac{-4}{5}.frac{13}{10}+frac{-4}{5}.frac{7}{10}-frac{-4}{5}
d.frac{frac{-2}{7}-frac{-2}{15}+frac{-2}{39}}{frac{5}{7}-frac{5}{15}+frac{5}{39}}
e.frac{3}{5}.frac{15}{7}-frac{15}{7}.frac{8}{5}
f.frac{2}{3}+frac{1}{3}.left(frac{-4}{9}+frac{5}{6}right):frac{7}{12}
h.frac{frac{3}{5}+frac{3}{7}-frac{3}{11}}{...
Đọc tiếp
1.tính các biểu thức sau bằng một cách hợp lí
a.\(\frac{108}{119}.\frac{107}{211}+\frac{108}{119}.\frac{104}{211}\)
b.\(\frac{15}{19}.\frac{27}{33}+\frac{15}{19}.\frac{19}{33}-\frac{15}{19}.\frac{13}{33}\)
c.\(\frac{-4}{5}.\frac{13}{10}+\frac{-4}{5}.\frac{7}{10}-\frac{-4}{5}\)
d.\(\frac{\frac{-2}{7}-\frac{-2}{15}+\frac{-2}{39}}{\frac{5}{7}-\frac{5}{15}+\frac{5}{39}}\)
e.\(\frac{3}{5}.\frac{15}{7}-\frac{15}{7}.\frac{8}{5}\)
f.\(\frac{2}{3}+\frac{1}{3}.\left(\frac{-4}{9}+\frac{5}{6}\right):\frac{7}{12}\)
h.\(\frac{\frac{3}{5}+\frac{3}{7}-\frac{3}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{11}}\)
g.\(\frac{3}{-4}+\frac{2}{7}+\frac{-1}{4}+\frac{5}{7}+\frac{21}{22}.\frac{66}{7}\)
k.\(\frac{27.18+27.103-120.27}{15.33+33.12}\)
l.\(\frac{\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{9}-\frac{4}{11}}\)
cho \(A=\frac{1}{3\cdot8}+\frac{1}{8\cdot13}+...+\frac{1}{33.38}\)
\(B=\frac{1}{3\cdot10}+\frac{1}{10\cdot17}+...+\frac{1}{31\cdot38}\)
tính tỉ số \(\frac{A}{B}\) \(\left(A⋮B\right)\)
Chứng Minh Rằng
a) \(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}< \frac{1}{3}\)
b) \(\frac{1}{3}-\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+.....+\frac{99}{3^{99}}-\frac{100}{3^{100}}< \frac{3}{16}\)
Tính hợp lí:
a, 75. ( -2frac{3}{25}+7frac{2}{75}-5frac{4}{15} )
b, 45.left(5frac{4}{15}-4frac{7}{9}-1frac{8}{45}right)
c, frac{-5}{8}+frac{14}{18}-frac{3}{8}+frac{2}{9}-frac{1}{2006}
d, frac{15}{29}-frac{8}{7}+frac{16}{14}+frac{14}{29}-frac{3}{8}
e, frac{1}{3.5}+frac{1}{5.7}+...+frac{1}{49.51}
Đọc tiếp
Tính hợp lí:
a, 75. ( \(-2\frac{3}{25}+7\frac{2}{75}-5\frac{4}{15}\) )
b, \(45.\left(5\frac{4}{15}-4\frac{7}{9}-1\frac{8}{45}\right)\)
c, \(\frac{-5}{8}+\frac{14}{18}-\frac{3}{8}+\frac{2}{9}-\frac{1}{2006}\)
d, \(\frac{15}{29}-\frac{8}{7}+\frac{16}{14}+\frac{14}{29}-\frac{3}{8}\)
e, \(\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{49.51}\)
1.tính giá trị biểu thức sau một cách hợp lí nếu có
a)\(\frac{1}{3}.\frac{4}{5}+\frac{1}{3}.\frac{6}{5}-\frac{5}{3}\)
b)\(\frac{4}{19}.\frac{-3}{7}+\frac{-3}{7}.\frac{15}{19}+\frac{5}{7}\)
c)\(\frac{6}{7}.\frac{10}{9}+\frac{1}{7}.\frac{10}{9}-\frac{8}{9}\)