Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(3+\frac{2}{5}-\frac{3}{4}\times\frac{4}{5}\)
\(=3+\frac{2}{5}-\frac{3}{4}\)
\(=\frac{3\times20+2\times4-3\times5}{20}\)
\(=\frac{60+8-15}{20}\)
\(=\frac{68-15}{20}\)
\(=\frac{53}{20}\)
\(5-\frac{7}{9}+\frac{2}{3}-\frac{5}{6}:\frac{4}{9}\)
\(=5-\frac{7}{9}+\frac{2}{3}-\frac{45}{24}\)
\(=\frac{5\times72-7\times8+2\times24-45\times3}{72}\)
\(=\frac{360-56+48-135}{72}\)
\(=\frac{217}{72}\)
\(\frac{1}{2}:\frac{3}{2}:\frac{5}{4}:\frac{6}{5}:\frac{7}{6}:\frac{8}{7}\)
\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\)
\(=\frac{1\cdot\left(2\cdot5\cdot6\cdot7\right)}{8\cdot3\cdot\left(2\cdot5\cdot6\cdot7\right)}\)
\(=\frac{1}{24}\)
\(\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\cdot\frac{8}{9}\cdot\frac{9}{10}\)
\(=\frac{1\cdot\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)}{\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)\cdot10}\)
\(=\frac{1}{10}\)
Bài 5:
Bài giải
Bác An đã bán được số gạo là:
\(45\times\frac{2}{5}=18\left(kg\right)\)
Bác An còn lại số gạo là:
\(45-18=27\left(kg\right)\)
Đ/S: 27 kg
Bài 1:
\(\frac{3}{4}-\frac{1}{6}=\frac{7}{12}\)
Bài 2:
\(\frac{9}{10}-x=\frac{1}{3}\)
\(x=\frac{9}{10}-\frac{1}{3}\)
\(x=\frac{17}{30}\)
Bài 3:
\(\frac{9}{8}-\frac{9}{14}=\frac{27}{56}\)
Bài 4:
\(\frac{4}{7}\times\frac{5}{3}=\frac{20}{21}\)
Bài 5:
Bài giải
Bác An đã bán được số gạo là:
Mình sửa lại đề xíu.
a) \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}=\frac{3}{4}+\frac{1}{4}+\frac{18}{21}+\frac{3}{21}+\frac{19}{32}+\frac{13}{32}=1+1+1=3\)
b) \(4\frac{2}{5}+5\frac{6}{9}+2\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}=4+\frac{2}{5}+\frac{3}{5}+5+\frac{2}{3}+\frac{1}{3}+2+\frac{3}{4}+\frac{1}{4}\)
\(=4+1+5+1+2+1=14.\)
c) \(\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+\frac{2}{7\cdot9}+...+\frac{2}{41\cdot43}=\frac{5-3}{3\cdot5}+\frac{7-5}{5\cdot7}+\frac{9-7}{7\cdot9}+...+\frac{43-41}{41\cdot43}\)
\(=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{41}-\frac{1}{43}=\frac{1}{3}-\frac{1}{43}=\frac{43-3}{3\cdot43}=\frac{40}{129}.\)
\(x+\frac{2}{3}=\frac{9}{11}\)
\(x=\frac{9}{11}-\frac{2}{3}\)
\(x=\frac{5}{33}\)
\(x-\frac{3}{10}=\frac{4}{15}\)
\(x=\frac{3}{10}-\frac{4}{15}\)
\(x=\frac{1}{10}\)
\(x\times\frac{1}{7}=\frac{5}{6}\)
\(x=\frac{5}{6}:\frac{1}{7}\)
\(x=\frac{35}{6}\)
\(x:\frac{3}{5}=\frac{1}{6}\)
\(x=\frac{3}{5}.\frac{1}{6}\)
\(x=\frac{1}{10}\)
+, \(x+\frac{2}{3}=\frac{9}{11}\)
\(x=\frac{9}{11}-\frac{2}{3}=\frac{5}{33}\)
+, \(x-\frac{3}{10}=\frac{4}{15}\)
\(x=\frac{4}{15}+\frac{3}{10}=\frac{17}{30}\)
+, \(x\cdot\frac{1}{7}=\frac{5}{6}\)
\(x=\frac{5}{6}:\frac{1}{7}=\frac{5}{6}.\frac{7}{1}=\frac{35}{6}\)
+,\(x:\frac{3}{5}=\frac{1}{6}\)
\(x=\frac{1}{6}\cdot\frac{3}{5}=\frac{3}{30}=\frac{1}{10}\)
\(\frac{1}{2}+\frac{1}{2}=\frac{1+1}{2}=\frac{2}{2}=1\)
\(\frac{3}{4}+\frac{1}{4}=\frac{3+1}{4}=\frac{4}{4}=1\)
\(\frac{3}{9}+\frac{6}{9}=\frac{3+6}{9}=\frac{9}{9}=1\)
a, 1/2+1/2=1
b, 3/4+1/4=1
c, 3/9+6/9=1
k nha bn, ok