bài 1 : Tính bằng cách hợp lí
a) \(\frac{0,4+\frac{2}{7}-\frac{2}{11}}{0,6+\frac{3}{7}-\frac{3}{11}}+\frac{0,25-0,2+\frac{1}{7}}{0,75-0,6+\frac{3}{7}}\)
K
Khách
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NM
26 tháng 6 2016
a) Ta có: \(\frac{0,4-\frac{2}{7}+\frac{2}{11}}{0,6-\frac{3}{7}+\frac{3}{11}}\)
\(=\frac{2.\left(0.2-\frac{1}{7}+\frac{1}{11}\right)}{3.\left(0,2-\frac{1}{7}+\frac{1}{11}\right)}\)
\(=\frac{2}{3}\)
b) Ta có: \(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{13}}\)
\(=\frac{3.\left(0,25-0,2+\frac{1}{7}+\frac{1}{13}\right)}{11.\left(0,25-0,2+\frac{1}{7}+\frac{1}{13}\right)}\)
\(=\frac{3}{11}\)
Chuk pạn hok tốt!
NA
26 tháng 6 2016
a) \(\frac{0,4-\frac{2}{7}+\frac{2}{11}}{0,6-\frac{3}{7}+\frac{3}{11}}\\ =\frac{\frac{2}{5}-\frac{2}{7}+\frac{2}{11}}{\frac{3}{5}-\frac{3}{7}+\frac{3}{11}}\\ =\frac{2\left(\frac{1}{5}-\frac{1}{7}+\frac{1}{11}\right)}{3\left(\frac{1}{5}-\frac{1}{7}+\frac{1}{11}\right)}\\=\frac{2}{3}\)
b) \(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{13}}\\=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{13}}\\=\frac{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{11\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}\\=\frac{3}{11}\)
N
20 tháng 7 2017
\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\)
\(=\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{2}{6}-\frac{2}{8}+\frac{2}{10}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)
\(=\frac{2.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7.\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}-\frac{2.\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}{7.\left(\frac{1}{6}-\frac{1}{8}+\frac{1}{10}\right)}\)
\(=\frac{2}{7}-\frac{2}{7}\)
\(=0\)
1 tháng 4 2019
\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}=\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)
\(=\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}-\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{2}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}\)
\(=\frac{2}{7}-\frac{1}{\frac{7}{2}}\)
\(=\frac{2}{7}-\frac{2}{7}=0\)
Study well ! >_<
S
29 tháng 6 2017
Câu 1;
\(\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}\cdot\frac{\frac{3}{4}-\frac{3}{16}-\frac{3}{64}-\frac{3}{256}}{1-\frac{1}{4}-\frac{1}{16}-\frac{1}{64}}+\frac{5}{8}\)
\(=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{2\left(\frac{1}{3}-\frac{1}{7}-\frac{1}{13}\right)}\cdot\frac{3\left(\frac{1}{4}-\frac{1}{16}-\frac{1}{64}-\frac{1}{256}\right)}{4\left(\frac{1}{4}-\frac{1}{16}-\frac{1}{64}-\frac{1}{256}\right)}+\frac{5}{8}\)
\(=\frac{1}{2}\cdot\frac{3}{4}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}=1\)
Câu 2:
\(\frac{0,75-0,6+\frac{3}{7}+\frac{3}{13}}{2,75-2,2+\frac{11}{7}+\frac{11}{3}}=\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}}{\frac{11}{4}-\frac{11}{5}+\frac{11}{7}+\frac{11}{3}}=\frac{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}{11\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right)}=\frac{3}{11}\)
29 tháng 6 2017
Câu 1;
13 −17 −113 23 −27 −213 ·34 −316 −364 −3256 1−14 −116 −164 +58
=13 −17 −113 2(13 −17 −113 ) ·3(14 −116 −164 −1256 )4(14 −116 −164 −1256 ) +58
=12 ·34 +58 =38 +58 =1
Câu 2:
9 tháng 5 2018
a, Ta có:
\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{0,6-\frac{3}{9}+\frac{3}{11}}+\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{14}}{-1-\frac{3}{7}+\frac{3}{28}}=\frac{2\left(0,2-\frac{1}{9}+\frac{1}{11}\right)}{3\left(0,2-\frac{1}{9}+\frac{1}{11}\right)}+\frac{2\left(\frac{1}{3}+\frac{1}{7}-\frac{1}{28}\right)}{-3\left(\frac{1}{3}+\frac{1}{7}-\frac{1}{28}\right)}=\frac{2}{3}+\frac{-2}{3}=0\)
k đúng cho mình nha. Thanks!!!
9 tháng 5 2018
a, bày cho mình cách viết bằng phân số đi , mình trình bày cách làm cho. k đúng cho mình nha.
KH
3
TM
13 tháng 6 2017
\(\frac{0,4-\frac{2}{7}+\frac{2}{11}}{0,6-\frac{3}{7}+\frac{3}{11}}=\frac{2\left(0,2-\frac{1}{7}+\frac{1}{11}\right)}{3\left(0,2-\frac{1}{7}+\frac{1}{11}\right)}=\frac{2}{3}\)
13 tháng 6 2017
\(\frac{0,4-\frac{2}{7}+\frac{2}{11}}{0,6-\frac{3}{7}+\frac{3}{11}}\)
\(=\frac{\frac{2}{5}-\frac{2}{7}+\frac{2}{11}}{\frac{3}{5}-\frac{3}{7}+\frac{3}{11}}\)
\(=\frac{2.\left(\frac{1}{5}-\frac{1}{7}+\frac{1}{11}\right)}{3.\left(\frac{1}{5}-\frac{1}{7}+\frac{1}{11}\right)}\)
\(=\frac{2}{3}\)
dễ mak