    elk       2.0   501.5
        moose     3.1   801.5

        Keys of a dictionary are aligned to the DataFrame, based on column names;
        each value in the dictionary is added to the corresponding column.

        >>> df[['height', 'weight']] + {'height': 0.5, 'weight': 1.5}
               height  weight
        elk       2.0   501.5
        moose     3.1   801.5

        When `other` is a :class:`Series`, the index of `other` is aligned with the
        columns of the DataFrame.

        >>> s1 = pd.Series([0.5, 1.5], index=['weight', 'height'])
        >>> df[['height', 'weight']] + s1
               height  weight
        elk       3.0   500.5
        moose     4.1   800.5

        Even when the index of `other` is the same as the index of the DataFrame,
        the :class:`Series` will not be reoriented. If index-wise alignment is desired,
        :meth:`DataFrame.add` should be used with `axis='index'`.

        >>> s2 = pd.Series([0.5, 1.5], index=['elk', 'moose'])
        >>> df[['height', 'weight']] + s2
               elk  height  moose  weight
        elk    NaN     NaN    NaN     NaN
        moose  NaN     NaN    NaN     NaN

        >>> df[['height', 'weight']].add(s2, axis='index')
               height  weight
        elk       2.0   500.5
        moose     4.1   801.5

        When `other` is a :class:`DataFrame`, both columns names and the
        index are aligned.

        >>> other = pd.DataFrame({'height': [0.2, 0.4, 0.6]},
        ...                      index=['elk', 'moose', 'deer'])
        >>> df[['height', 'weight']] + other
               height  weight
        deer      NaN     NaN
        elk       1.7     NaN
        moose     3.0     NaN
        N)