Question

20-[30-(1-5)²:2]

Answer 1

\(20-\left[30-\left(1-5\right)^2:2\right]\)

\(=20-30+\left(-4\right)^2:2\)

=-10+16:2

=-10+8

=-2

Answer 2

$20-[30-(1-5)^2:2]$

$=20-[30-(-4)^2:2]$

$=20-(30-4^2:2)$

$=20-(30-16:2)$

$=20-(30-8)$

$=20-22$

$=-2$

Answer 3

\(20-[30-\left(1-5\right)^2:2]\\ =20-\left(30+4^2:2\right)\\= 20-\left(30+8\right)\\ =20-38\\ =-18\)