What I want to do:
+------+--------+---------+-----------+----------+--------+-------+------------+
| Week | Monday | Tuesday | Wednesday | Thursday | Friday | Total | Difference |
+------+--------+---------+-----------+----------+--------+-------+------------+
| 1 | 8 | 8 | 8 | 9 | 8 | 41 | 1 |
+------+--------+---------+-----------+----------+--------+-------+------------+
| 2 | 8 | 8 | 8 | 8 | 8 | 40 | 0 |
+------+--------+---------+-----------+----------+--------+-------+------------+
| 3 | 8 | 8 | | | | | |
+------+--------+---------+-----------+----------+--------+-------+------------+
In the above table, I want a formula in the 'total' column that will only sum the values from Monday to Friday when all five cells contain a value. If any of the cells are empty then it shouldn't sum them. How can I do this?