+---+   +---+   +---+   +---+   +---+   
| 4 |-->| ● |-->| 9 |-->| ● |-->| 7 |
+---+   +---+   +---+   +---+   +---+
  ^       ^       ^       ^       ^
  |       |       |       |       |      
+---+   +---+   +---+   +---+   +---+   
| ● |-->| 7 |-->| ● |-->| 5 |-->| ● |
+---+   +---+   +---+   +---+   +---+
  ^       ^       ^       ^       ^
  |       |       |       |       |      
+---+   +---+   +---+   +---+   +---+   
| 5 |-->| ● |-->| 9 |-->| ● |-->| 4 |
+---+   +---+   +---+   +---+   +---+  
  ^       ^       ^       ^       ^
  |       |       |       |       |      
+---+   +---+   +---+   +---+   +---+   
| ● |-->| 8 |-->| ● |-->| 6 |-->| ● |
+---+   +---+   +---+   +---+   +---+
  ^       ^       ^       ^       ^ 
  |       |       |       |       |      
+---+   +---+   +---+   +---+   +---+   
| 6 |-->| ● |-->| 8 |-->| ● |-->| 5 |
+---+   +---+   +---+   +---+   +---+

Move from the bottom left-hand 6 to the top right-hand 7 in the direction of the arrows, adding together all the five numbers .

Each black circle is worth minus 5 and this will be taken from the total each time you meet one.

How many different routes are there- each giving a total of 10 ?