cpp/chrono/year month weekday/operator arith 2

@1-2@ Adds months to the date represented by. The result has the same and  as  and the same  and  as. @3-4@ Adds years to the date represented by. The result is equivalent to. @5@ Subtracts months from the date represented by. Equivalent to. @6@ Subtracts years from the date represented by. Equivalent to.

For durations that are convertible to both std and std, the overloads  are preferred if the call would otherwise be ambiguous.