Answer
$1$
Work Step by Step
$a=i+j=\lt 1,1,0\gt $
$b=j+k=\lt 0,1,1\gt $
$a=i+j+k=\lt 1,1,1\gt $
Volume of a parallelepiped is defined as:
$V=|a \cdot (b \times c)|$
$b \times c= \lt 0,1,1 \gt \times \lt 1,1,1 \gt=\lt 0,1,-1 \gt$
$|a \cdot (b \times c)|= |\lt 1,1,0 \gt \cdot \lt 0,1,-1 \gt|$
$=|1 \cdot 0+1 \cdot 1+ 0 \cdot (-1)|$
$=|1|$
$=1$
