1 files changed, 87 insertions, 0 deletions
diff --git a/docs/docs/addition_subtraction.md b/docs/docs/addition_subtraction.md
new file mode 100644
index 0000000..686f67f
--- /dev/null
+++ b/docs/docs/addition_subtraction.md
@@ -0,0 +1,87 @@
+# Addition and Subtraction
+
+To easily add and subtract time, you can use the `add()` and `subtract()`
+methods.
+Each method returns a new `DateTime` instance.
+
+```python
+>>> import pendulum
+
+>>> dt = pendulum.datetime(2012, 1, 31)
+
+>>> dt.to_datetime_string()
+'2012-01-31 00:00:00'
+
+>>> dt = dt.add(years=5)
+'2017-01-31 00:00:00'
+>>> dt = dt.add(years=1)
+'2018-01-31 00:00:00'
+>>> dt = dt.subtract(years=1)
+'2017-01-31 00:00:00'
+>>> dt = dt.subtract(years=5)
+'2012-01-31 00:00:00'
+
+>>> dt = dt.add(months=60)
+'2017-01-31 00:00:00'
+>>> dt = dt.add(months=1)
+'2017-02-28 00:00:00'
+>>> dt = dt.subtract(months=1)
+'2017-01-28 00:00:00'
+>>> dt = dt.subtract(months=60)
+'2012-01-28 00:00:00'
+
+>>> dt = dt.add(days=29)
+'2012-02-26 00:00:00'
+>>> dt = dt.add(days=1)
+'2012-02-27 00:00:00'
+>>> dt = dt.subtract(days=1)
+'2012-02-26 00:00:00'
+>>> dt = dt.subtract(days=29)
+'2012-01-28 00:00:00'
+
+>>> dt = dt.add(weeks=3)
+'2012-02-18 00:00:00'
+>>> dt = dt.add(weeks=1)
+'2012-02-25 00:00:00'
+>>> dt = dt.subtract(weeks=1)
+'2012-02-18 00:00:00'
+>>> dt = dt.subtract(weeks=3)
+'2012-01-28 00:00:00'
+
+>>> dt = dt.add(hours=24)
+'2012-01-29 00:00:00'
+>>> dt = dt.add(hours=1)
+'2012-02-25 01:00:00'
+>>> dt = dt.subtract(hours=1)
+'2012-02-29 00:00:00'
+>>> dt = dt.subtract(hours=24)
+'2012-01-28 00:00:00'
+
+>>> dt = dt.add(minutes=61)
+'2012-01-28 01:01:00'
+>>> dt = dt.add(minutes=1)
+'2012-01-28 01:02:00'
+>>> dt = dt.subtract(minutes=1)
+'2012-01-28 01:01:00'
+>>> dt = dt.subtract(minutes=24)
+'2012-01-28 00:00:00'
+
+>>> dt = dt.add(seconds=61)
+'2012-01-28 00:01:01'
+>>> dt = dt.add(seconds=1)
+'2012-01-28 00:01:02'
+>>> dt = dt.subtract(seconds=1)
+'2012-01-28 00:01:01'
+>>> dt = dt.subtract(seconds=61)
+'2012-01-28 00:00:00'
+
+>>> dt = dt.add(years=3, months=2, days=6, hours=12, minutes=31, seconds=43)
+'2015-04-03 12:31:43'
+>>> dt = dt.subtract(years=3, months=2, days=6, hours=12, minutes=31, seconds=43)
+'2012-01-28 00:00:00'
+```
+
+!!!note
+
+    Passing negative values to `add()` is also possible and will act exactly
+    like `subtract()`