Løsning del 1 utrinn Vår 15 eksempeloppgave

Oppgave 1

a) $987 + 589 = 1576$

b) $8643 - 4789 = 3854$

c) $345 \cdot 678 = 233 910$

d) $32:0.64 = 50$

Oppgave 2

a) $205 \text{min} = 3 \text{h} 25 \text{min}$

b) $8 000 \text{mg} = 0.008 \text{kg}$

c) $750 \text{mL} = 0.75\text{L}$

d) $1 \text{daa (dekar)} = 1000 m^2$

$11 500 m^2 = 11.5 \cdot 1000 m^2 = 11.5 \text{daa (dekar)}$

Oppgave 3

a) $\frac{3}{10} \cdot 15 = \frac{3 \cdot 15}{10} = \frac{45}{10} = \frac{9}{2} = 4 \frac12 $

b) $6:\frac{3}{4} = 6 \cdot \frac{4}{3} = \frac{6 \cdot 4}{3}= \frac{24}{3} = 8$

Oppgave 4

a) $1 + 2 \cdot (3-4) ^2 = 3 $

b) $ -5 \cdot (-2 + 4) ^2 - {2^3 \over 4 } = -22$

Oppgave 5

a) $x + 3 = -3x +7$

$x + 3x+ 3 = 7$

$x + 3x = 7 - 3$

$4x = 4$

$x = 1$

b) $\frac{x}{6} - \frac{2-x}{4} = \frac{x}{3} +1$

$\frac{x}{6} - \left(\frac{2}{4} + \frac{-x}{4}\right)= \frac{x}{3} +1$

$\frac{x}{6} - \left(\frac{2}{4} - \frac{x}{4}\right)= \frac{x}{3} +1$

$\frac{x}{6} - \frac{2}{4} + \frac{x}{4}= \frac{x}{3} +1$

$\frac{x}{6} + \frac{x}{4}= \frac{x}{3} +1 + \frac{2}{4}$

$\frac{x}{6} + \frac{x}{4} - \frac{x}{3} = 1 + \frac{2}{4}$

$\frac{x}{6}\cdot 12 + \frac{x}{4}\cdot 12 - \frac{x}{3}\cdot 12 = 1\cdot 12 + \frac{2}{4}\cdot 12$

$x \cdot 2 + x \cdot 3 - x \cdot 4 = 12 + 2 \cdot 3$

$x = 18 $