Bài 3:
a: Ta có: \(x+\dfrac{2}{9}=1\)
nên \(x=\dfrac{7}{9}\)
b: Ta có: \(\dfrac{8}{7}-x=\dfrac{4}{7}\)
nên \(x=\dfrac{4}{7}\)
c: Ta có: \(\dfrac{3}{4}:x=\dfrac{1}{4}\)
nên x=3
d: Ta có: \(\dfrac{2}{3}\cdot x=\dfrac{1}{5}\)
nên \(x=\dfrac{3}{10}\)
Bài 2:
a: \(325\cdot6+6\cdot560+115\cdot6\)
\(=6\cdot\left(325+560+115\right)\)
\(=6\cdot1000=6000\)
b: \(133:7+154:7+413:7\)
\(=\left(133+154+413\right):7\)
\(=100\)
c: \(64\cdot25+35\cdot25+25\)
\(=25\cdot\left(64+35+1\right)\)
=2500
d: \(22\cdot47+2\cdot38\cdot11+15\cdot22\)
\(=22\left(47+38+15\right)\)
\(=22\cdot100=2200\)
Bài 1:
a: \(\dfrac{6}{7}+\dfrac{5}{8}=\dfrac{83}{56}\)
b: \(\dfrac{7}{11}+\dfrac{3}{4}+\dfrac{4}{11}+\dfrac{1}{4}=2\)
4 và 5
