Question

Calcule o valor das expressões numéricas (expressoẽs na imagem)

Answer 1

B
$\frac{1}{2}-(\frac{1}{4}-1-0,3)-(-0,9+\frac{4}{5})=$
$\frac{1}{2}-(\frac{1-1*4-0,3*4}{4})-(\frac{-0,9*5+4}{5})=$
$\frac{1}{2}-(\frac{1-4-1,2}{4})-(\frac{-4,5+4}{5})=$
$\frac{1}{2}-(\frac{1-5,2}{4})-(\frac{-0,5}{5})=$
$\frac{1}{2}-(\frac{-4,2}{4})-(-0,1)=$
$\frac{1}{2}+\frac{4,2}{4}+0,1=$
$\frac{1*2+4,2+0,4}{4}=$
$\frac{2+4,2+0,4}{4}=$
$\frac{6,6}{4}=\boxed{\boxed{1,65}}$

C
$1,5-[-2-(-2,4+\frac{1}{2}+\frac{1}{5})]=$
$1,5-[-2-(\frac{-2,4*10+1*5+1*2}{10})]=$
$1,5-[-2-(\frac{-24+5+2}{10})]=$
$1,5-[-2-(\frac{-24+7}{10})]=$
$1,5-[-2-(\frac{-17}{10})]=$
$1,5-[-2+\frac{17}{10})]=$
$1,5-[\frac{-2*10+17}{10})]=$
$1,5-[\frac{-20+17}{10})]=$
$1,5-[\frac{-3}{10})]=$
$1,5+\frac{3}{10})]=$
$\frac{1,5*10+3}{10})]=$
$\frac{15+3}{10})]=$
$\frac{18}{10})]=\boxed{\boxed{1,8}}$

D
$0,3-[-1,2+(+2,5-0,25)+1,6]=$
$0,3-[-1,2+(+2,25)+1,6]=$
$0,3-[-1,2+2,25+1,6]=$
$0,3-[-1,2+3,85]=$
$0,3-[2,65]=$
$0,3-2,65=\boxed{\boxed{-2,35}}$