Question

Escreva, no caderno, o resultado das operações na forma decimal.
A)-3,1+(2,4-3,8)-(1,6-2)
B)-9/2+[-1-(-5/8+1/4)]
C)7/3-[2-(1/3-1)]
D)1/8+(1/4)

Answer 1

A)-3,1+(2,4-3,8)-(1,6-2) =

-3,1+(-1,4)-(-0,4) =

-3,1 - 1,4 + 0,4 = -4,1

B)-9/2+[-1-(-5/8+1/4)] =

-4,5+[-1-(-0,625+0,25)] =

-4,5+[-1-(-0,375)] =

-4,5+[-1+0,375] =

-4,5+[-0,625] =

-4,5-0,625 =-5,125

C)7/3-[2-(1/3-1)] =

7/3-[2-(-2/3)] =

7/3-[8/3] =

7/3-8/3 = -1/3 = -0,3333....

D)1/8+(1/4)=

0,125 + 0,25 = 0,375

Answer 2

Explicação passo-a-passo:

a)

$\sf -3,1+(2,4-3,8)-(1,6-2)$

$\sf =-3,1-1,4-(-0,4)$

$\sf =-3,1-1,4+0,4$

$\sf =-4,5+0,4$

$\sf =\red{-4,1}$

b)

$\sf -\dfrac{9}{2}+\left[-1-\left(-\dfrac{5}{8}+\dfrac{1}{4}\right)\right]$

$\sf =-4,5+[-1-(-0,625+0,25)]$

$\sf =-4,5+[-1-(-0,375)]$

$\sf =-4,5+[-1+0,375]$

$\sf =-4,5-0,625$

$\sf =\red{-5,125}$

c)

$\sf \dfrac{7}{3}-\left[2-\left(\dfrac{1}{3}-1\right)\right]$

$\sf =2,333...-[2-(0,333...-1)]$

$\sf =2,333...-[2-(-0,666...)]$

$\sf =2,333...-[2+0,666...]$

$\sf =2,333...-2,666...$

$\sf =\red{-0,333...}$

d)

$\sf \dfrac{1}{8}+\dfrac{1}{4}$

$\sf =0,125+0,25$

$\sf =\red{0,375}$