\(\dfrac{7}{130}+\dfrac{-7}{52}=\dfrac{14}{260}+\dfrac{-35}{260}=\dfrac{14+\left(-35\right)}{260}=\dfrac{-21}{260}\)
\(\dfrac{7}{130}+\dfrac{-7}{52}=\dfrac{14}{260}+\dfrac{-35}{260}=\dfrac{14+\left(-35\right)}{260}=\dfrac{-21}{260}\)
a, \(\left|x\right|\)- \(\dfrac{38}{7}\)\(\left|x\right|\)= 2\(\left|x\right|\)+ (\(\dfrac{-8}{7}\))
b, \(\dfrac{83}{15}\): x + (\(\dfrac{-4}{17}\)) : x + \(\dfrac{22}{7}\): \(\dfrac{52}{3}\)= \(\dfrac{4}{11}\)
Tính tỉ số \(\dfrac{A}{B}\) biết \(A=\dfrac{4}{7.31}+\dfrac{6}{7.41}+\dfrac{9}{10.41}+\dfrac{7}{10.57}\) và \(B=\dfrac{7}{19.31}+\dfrac{5}{19.43}+\dfrac{3}{23.43}+\dfrac{11}{23.57}\)
\(\text{Câu 1: Cho các số A và B. Hãy tính tỉ số }\)\(\dfrac{A}{B}\) \(biết:\)
\(a\)) \(A=\dfrac{4}{7.31}+\dfrac{6}{7.41}+\dfrac{9}{10.41}+\dfrac{7}{10.57};\)
\(B=\dfrac{7}{19.31}+\dfrac{5}{19.43}+\dfrac{3}{23.43}+\dfrac{11}{23.57}\)
\(b\)) \(A=\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{2021};\)
\(B=\dfrac{2020}{1}+\dfrac{2019}{2}+\dfrac{2018}{3}+...+\dfrac{1}{2020}\)
Tính:
\(\dfrac{7}{13}.\dfrac{5}{19}+\dfrac{7}{19}.\dfrac{8}{13}-3.\dfrac{7}{19}\)
Thực hiện phép tính: \(\dfrac{-3}{8}.\dfrac{2}{7}+\dfrac{-3}{8}.\dfrac{5}{7}+\left|\dfrac{-7}{8}\right|\)
Tính nhanh:
\(A=\dfrac{5}{13}=\dfrac{-5}{7}+\dfrac{-20}{41}+\dfrac{8}{13}+\dfrac{-21}{41}\)
Tính:
\(A=\)\(\dfrac{1}{5}+\left(\dfrac{-1}{3}+\dfrac{9}{5}\right)+\dfrac{-7}{6}\)
\(\text{Thực hiện phép tính một cách hợp lý nhất (nếu có thể):}\)
\(1\)) \(\left(\dfrac{-8}{13}:\dfrac{3}{7}+\dfrac{-5}{13}:\dfrac{3}{7}\right).\dfrac{\left(-4\right)^3.\left|-3\right|}{7}\)
\(2\)) \(75\)\(\text{%}\)\(-\left(\dfrac{5}{2}+\dfrac{5}{3}\right)+\left(-\dfrac{1}{2}\right)^2\)
SS A và B
A=\(\dfrac{19}{24}-\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{7}{24}\)
B=\(\dfrac{7}{24}+\dfrac{5}{6}+\dfrac{1}{4}-\dfrac{3}{7}-\dfrac{5}{15}\)