$${\mathtt{5.2}}\%{\mathtt{\,\times\,}}{\mathtt{25\,900}} = {\frac{{\mathtt{6\,734}}}{{\mathtt{5}}}} = {\mathtt{1\,346.8}}$$
$${\frac{{\mathtt{15}}}{\left(-{\mathtt{5}}\right)}} = -{\mathtt{3}}$$ ; $${\frac{{\mathtt{66}}}{\left(-{\mathtt{11}}\right)}} = -{\mathtt{6}}$$
http://www.mathe-lexikon.at/arithmetik/ganze-zahlen/die-4-grundrechnungsarten/dividieren-mit-ganzen-zahlen/dividieren-von-positiven-durch-negativen-ganzen-zahlen.html
$${\mathtt{65}}{\mathtt{\,\times\,}}{\mathtt{0.52}}{euro} = {\mathtt{33.8}}{euro}$$
$${\mathtt{7}}{\mathtt{\,\times\,}}{\mathtt{8}} = {\mathtt{56}}$$
a) = 39a+66b
b) =-18g-10d
c) =-33x+13y
d) =-23s+13
e) -2,4v-8,8u
f) = 35x-30-35x-20=-50
g) =-22+3a+19-8a=-5a-3
h) =-9x-27y-7x+17y=-16x-10y
i) = 1,5a-9,6b-24-2,3a-6b=-0,8a-15,6b-24
$${\mathtt{\,-\,}}{\mathtt{2.432\: \!856\: \!7}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3}}{\mathtt{\,\small\textbf+\,}}{ln}{\left({\mathtt{\,-\,}}{\mathtt{2.432\: \!856\: \!7}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3}}\right)} = {\mathtt{0.000\: \!000\: \!026\: \!499\: \!904}}$$