Arithmetic predicates

X is E

Evaluate E and unify the result with X.

X + Y

When evaluated, yields the sum of X and Y.

X - Y

When evaluated, yields the difference of X and Y.

X * Y

When evaluated, yields the product of X and Y.

X / Y

When evaluated, yields the quotient of X and Y.

X mod Y

When evaluated, yields the remainder of X divided by Y.

X =:= Y

Evaluate X and Y and compare them for equality.

X =\= Y

Evaluate X and Y and succeed if they are not equal.

...and similarly for >, <, >=, =<.