X is E
E
and unify the result with X
.
X + Y
X
and Y
.
X  Y
X
and Y
.
X * Y
X
and Y
.
X / Y
X
and Y
.
X mod Y
X
divided by Y
.
X =:= Y
X
and Y
and compare them for equality.
X =\= Y
X
and Y
and succeed if they are not equal.
...and similarly for >
, <
, >=
, =<
.

