a)\(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=1+\left(\frac{4}{9}+\frac{3}{9}\right)+3\)
\(=1+\frac{7}{9}+3\)
\(=1+3+\frac{7}{9}\)
\(=4\frac{7}{9}\)
\(=\frac{43}{9}\)
b)\(\frac{8}{5}\cdot\frac{4}{7}+\frac{4}{7}\cdot\frac{2}{5}-1\)
\(=\frac{4}{7}\cdot\left(\frac{8}{5}+\frac{2}{5}\right)-1\)
\(=\frac{4}{7}\cdot2-1\)
\(=\frac{8}{7}-1\)
\(=\frac{1}{7}\)
a) \(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{3}{9}\right)+3\)
\(=1+\frac{7}{9}+3=4\frac{7}{9}\)
b)\(\frac{8}{5}.\frac{4}{7}+\frac{4}{7}.\frac{2}{5}-1\)
\(=\frac{4}{7}.\left(\frac{8}{5}+\frac{2}{5}\right)-1\)
\(=\frac{4}{7}.2-1\)
\(=\frac{8}{7}-\frac{7}{7}=\frac{1}{7}\)
a) 8/13+5/13+4/9+1/3+3=1+4/9+1/3+3=1+7/9+3=43/9
b)2x4/7-1=8/7-1=1/7
Bạn có thể tính theo cách của mình thì nhanh hơn nhưng rất dễ nhầm lẫn,nếu bạn chưa thành thạo dạng toán này thì bạn nên tính từng số,nếu thành thạo bạn có thể tính theo cách của mình.
cảm ơn mọi người mk lm theo cách tính nhanh cho dễ
a) \(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{13}+3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=1+\left(\frac{4}{9}+\frac{3}{9}\right)+3\)
\(=1+\frac{7}{9}+3\)
\(=\frac{9}{9}+\frac{7}{9}+\frac{27}{9}=\frac{43}{9}\)
b) \(\frac{8}{5}.\frac{4}{7}+\frac{4}{7}.\frac{2}{5}-1\)
\(=\frac{4}{7}.\left(\frac{8}{5}+\frac{2}{5}\right)-1\)
\(=\frac{4}{7}.2-1\)
\(=\frac{8}{7}-1\)
\(=\frac{8}{7}-\frac{7}{7}\)
\(=\frac{1}{7}\)
a) \(\frac{8}{13}+\frac{4}{9}+\frac{1}{3}+\frac{5}{18}+3\)
\(=\left(\frac{8}{13}+\frac{5}{13}\right)+\left(\frac{4}{9}+\frac{1}{3}\right)+3\)
\(=1+\left(\frac{4}{9}+\frac{3}{9}\right)+3\)
\(=1+\frac{7}{9}+3\)
\(=\left(1+3\right)+\frac{7}{9}\)
\(=4+\frac{7}{9}\)
\(=\frac{4}{1}+\frac{7}{9}\)
\(=\frac{36}{9}+\frac{7}{9}\)
\(=\frac{43}{9}\)
b) \(\frac{8}{5}\times\frac{4}{7}+\frac{4}{7}\times\frac{2}{5}-1\)
\(=\frac{4}{7}\times\left(\frac{8}{5}+\frac{2}{5}\right)-1\)
\(=\frac{4}{7}\times2-1\)
\(=\frac{4\times2}{7}-1\)
\(=\frac{8}{7}-1\)
\(=\frac{8}{7}-\frac{1}{1}\)
\(=\frac{8}{7}-\frac{7}{7}\)
\(=\frac{1}{7}\)
