a)
-\frac{1}{2}+\frac{2}{3}[\frac{3}{5}-(0,45)]=
-\frac{3}{6}+\frac{4}{6}(0,6-0,45)=\frac{1}{6}*\frac{15}{100}=\frac{15}{600}=0,025
[1,35- (-1$\frac{2}{5})]/ 2\frac{3}{4}=
(1,35+1,4)/2,75=2,75:2,75=1$
b)
\sqrt{5\frac{4}{9}} - (\frac{1}{3})^{-2} / 4\frac{1}{2}=\sqrt{\frac{49}{9}}-3^2/\frac{9}{2}=\frac{7}{3}-9/\frac{9}{2}=\frac{7}{3}-\frac{27}{3}/\frac{9}{2}=\frac{7}{3}-\frac{27}{3}*\frac{2}{9}=
2\frac{1}{3}-2=\frac{1}{3}
(8-3*2 \frac{1}{3})*(\frac{1}{3})^{-1}=(8-3*\frac{7}{3})*3^1=(8-7)*3=3
c)
2^32^22^5=2^{3+2+5}=2^{10}
2^3*2^6=2^9
d)
2^{19}* 27^3+ 15 + 4^9 * 9^4=2^{19} * 3^9 + 15 + 2^{18} * 3^8 =2*2^{18}*3 * 3^8+15+2^{18}*3^8=
2^{18}*3^8 ( 2 *3 + 1) + 15 = 7 * 2^{18} * 3^8 + 15
6^9* 2^{10}+ 12^{10}=6^9*2*2^9+12*12^9=2*12^9+12*12^9=12^9(2+12)=14*12^9