If 4/5 x blank = 2/5 what is blank
\(\frac{4}{5} \cdot x = \frac{2 }{5} \ \ /\cdot 5\\ \\ ot5^{1}\cdot \frac{4}{ ot5^{1}} \cdot x = ot5^{1 } \cdot \frac{2 }{ ot5^{1}}\\ \\4x=2 \ \ /:4 \\ \\x=\frac{2}{4}\\ \\x=\frac{1}{2}\)
\(\frac{4}{5}\cdot\fbox{\ }=\frac{2}{5}\ \ \ \ /\cdot\frac{5}{4}\\\\\frac{ ot5^1}{ ot4_1}\cdot\frac{ ot4^1}{ ot5_1}\cdot\fbox{\ }=\frac{ ot5^1}{ ot4_2}\cdot\frac{ ot2^1}{ ot5_1}\\\\\fbox{\ }=\frac{1}{2}\)
