I think there's a grammar error that crept in. Try the sql without the comma at the end of line 5. i.e.
SELECT a.fruit,
a.f_num,
b.c_num,
b.color
FROM sec1306_fruits a
INNER JOIN sec1306_colors b
ON a.f_num = b.c_num
ORDER BY a.fruit;
The statement above is modeled on the statement below. The syntax structure was pulled from
http://www.w3schools.com/sql/sql_join.asp
SELECT field1, field2, field3
FROM first_table
INNER JOIN second_table
ON first_table.keyfield = second_table.foreign_keyfield
[then you can order your result]