[tex]\it 1)\ \ (2^3)^8:2^{21}-4:4=2^{24}:2^{21}-1=2^3-1=8-1=7\\ \\ 2)\ \ 1+2+5+10\\ \\ 3)\ \ [DE]\equiv[DF][/tex]
[tex]\it II)\ \ 2\dfrac{2}{5}-1\dfrac{2}{5}=1\\ \\ \\ 0,2(3)=\dfrac{23-2}{90}=\dfrac{\ 21^{(3}}{90}=\dfrac{7}{30}[/tex]
Exercițiul devine:
[tex]\it \Big(1-\dfrac{1}{6}\Big):\Big(\dfrac{7}{30}\cdot\dfrac{10}{7}+\dfrac{1}{2}\Big)^2=\dfrac{5}{6}:\Big(\dfrac{1}{3}+\dfrac{1}{2}\Big)^2=\dfrac{5}{6}:\Big(\dfrac{5}{6}\Big)^2=\dfrac{5}{6}\cdot\dfrac{36}{25}=\dfrac{6}{5}=1,2[/tex]