Ôn tập toán 6
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Mấy bạn giúp mình vớiBài 1:Chứng minh rằng:a)frac{1}{1}-frac{1}{2}+frac{1}{3}-frac{1}{4}+...+frac{1}{9}-frac{1}{10}frac{1}{6}+frac{1}{7}+frac{1}{8}+frac{1}{9}+frac{1}{10}b)frac{1}{1times2}+frac{1}{3times4}+frac{1}{5times6}+...+frac{1}{400}frac{1}{201}+frac{1}{202}+...+frac{1}{400}
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Mấy bạn giúp mình với
Bài 1:Chứng minh rằng:
a)\(\frac{1}{1}-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{10}=\frac{1}{6}+\frac{1}{7}+\frac{1}{8}+\frac{1}{9}+\frac{1}{10}\)
b)\(\frac{1}{1\times2}+\frac{1}{3\times4}+\frac{1}{5\times6}+...+\frac{1}{400}=\frac{1}{201}+\frac{1}{202}+...+\frac{1}{400}\)
CMR: \(\frac{3}{1.2.3}+\frac{5}{2.3.4}+\frac{7}{3.4.5}+...+\frac{201}{100.101.102}< \frac{5}{4}\)
1)So sánh các số
a.200/201+201/202 và 200+201/201+202
Tìm x
a / (6 frac{2}{7} .x + frac{3}{7} ): 2frac{1}{5} - frac{3}{7} -1
b/ 5 frac{8}{17} : x + (- frac{1}{17}): x + 3 frac{1}{17}: 17frac{1}{3} frac{4}{17}
c/ frac{1}{1.4}+frac{1}{4.7}+frac{7}{7.10}+ ...+ frac{1}{xleft(x+3right)} frac{6}{19}
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Tìm x
a / (6 \(\frac{2}{7}\) .x + \(\frac{3}{7}\) ): 2\(\frac{1}{5}\) - \(\frac{3}{7}\) = -1
b/ 5 \(\frac{8}{17}\) : x + (- \(\frac{1}{17}\)): x + 3 \(\frac{1}{17}\): 17\(\frac{1}{3}\)= \(\frac{4}{17}\)
c/ \(\frac{1}{1.4}\)+\(\frac{1}{4.7}\)+\(\frac{7}{7.10}\)+ ...+ \(\frac{1}{x\left(x+3\right)}\)= \(\frac{6}{19}\)
tính hợp lý giá trị các biểu thức sau :A 49frac{8}{23}-left(5frac{7}{32}+14frac{8}{23}right)B 71frac{38}{45}-left(43frac{8}{45}-1frac{17}{57}right)C frac{-3}{7}.frac{5}{9}+frac{4}{9}.frac{-3}{7}+2frac{3}{7}D left(19frac{5}{8}:frac{7}{12}-13frac{1}{4}:frac{7}{12}right).frac{4}{5}E 0,7.2frac{2}{3}.20.0,375.frac{5}{28}F left(9,75.21frac{3}{7}+frac{39}{4}.18frac{4}{7}right).frac{15}{78}
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tính hợp lý giá trị các biểu thức sau :
A= \(49\frac{8}{23}-\left(5\frac{7}{32}+14\frac{8}{23}\right)\)
B= \(71\frac{38}{45}-\left(43\frac{8}{45}-1\frac{17}{57}\right)\)
C= \(\frac{-3}{7}.\frac{5}{9}+\frac{4}{9}.\frac{-3}{7}+2\frac{3}{7}\)
D = \(\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right).\frac{4}{5}\)
E= \(0,7.2\frac{2}{3}.20.0,375.\frac{5}{28}\)
F= \(\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right).\frac{15}{78}\)
a) Efrac{1}{1.2.3}+frac{1}{2.3.4}+...+frac{1}{48.49.50}
b) Ffrac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}
c) Gfrac{636363.37-373737.63}{1+2+3+...+2017}
d) Hleft(frac{12+frac{12}{19}-frac{12}{37}-frac{12}{53}}{3+frac{1}{3}-frac{3}{37}-frac{3}{53}}:frac{4+frac{4}{17}+frac{4}{19}+frac{4}{2016}}{5+frac{5}{17}+frac{5}{19}+frac{5}{3016}}right).frac{124242423}{237373735}
giúp mk với ! Help me!
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a) \(E=\frac{1}{1.2.3}+\frac{1}{2.3.4}+...+\frac{1}{48.49.50}\)
b) \(F=\frac{5.4^{15}.9^9-4.3^{20}.8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)
c) \(G=\frac{636363.37-373737.63}{1+2+3+...+2017}\)
d) \(H=\left(\frac{12+\frac{12}{19}-\frac{12}{37}-\frac{12}{53}}{3+\frac{1}{3}-\frac{3}{37}-\frac{3}{53}}:\frac{4+\frac{4}{17}+\frac{4}{19}+\frac{4}{2016}}{5+\frac{5}{17}+\frac{5}{19}+\frac{5}{3016}}\right).\frac{124242423}{237373735}\)
giúp mk với ! Help me!
tìm x biết :a) left(x+frac{1}{2}right).left(frac{2}{3}-2xright)0b) left(x.6frac{2}{7}+frac{3}{7}right).2frac{1}{5}-frac{3}{7}-2c) x.3frac{1}{4}+left(-frac{7}{6}right).x-1frac{2}{3}frac{5}{12}d) 5frac{8}{17}:x+left(-frac{4}{17}right):x+3frac{1}{7}:17frac{1}{3}frac{4}{11}e) frac{17}{2}-left|2x-frac{3}{4}right|-frac{7}{4}
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tìm x biết :
a) \(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
b) \(\left(x.6\frac{2}{7}+\frac{3}{7}\right).2\frac{1}{5}-\frac{3}{7}=-2\)
c) \(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)
d) \(5\frac{8}{17}:x+\left(-\frac{4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}=\frac{4}{11}\)
e) \(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)
Tính hợp lí:
A = \(\left(\frac{-4}{5}+\frac{4}{3}\right)+\left(\frac{-5}{4}+\frac{14}{5}\right)-\frac{7}{3}\)
B= \(\frac{8}{3}.\frac{2}{5}.\frac{3}{8}.10.\frac{19}{92}\)
C= \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{14}+1\frac{5}{7}\)
Bài 4: THực hiện phép tính một cách hợp lý:
a) \(\frac{7}{19}.\frac{8}{11}+\frac{3}{11}.\frac{7}{19}+\frac{-12}{19}\) b) \(\frac{-7}{25}.\frac{39}{-14}.\frac{50}{78}\) c) \(\left(\frac{3}{8}+\frac{-3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)