### Interval Operators

| Operator | Arguments            | Description                  |
| -------- | -------------------- | ---------------------------- |
| +        | (Interval, Interval) | addition two intervals       |
| -        | (Interval, Interval) | subtraction two intervals    |
| \*       | (Interval, Interval) | multiplication two intervals |
| /        | (Interval, Interval) | division two intervals       |


| Name          | Parameters | Return   | Description                                               |
| ------------- | ---------- | -------- | --------------------------------------------------------- |
| JUSTIFY_DAYS  | Interval   | Interval | Adjust interval, converting 30-day time periods to months |
| JUSTIFY_HOURS | Interval   | Interval | Adjust interval, converting 24-hour time periods to days  |
