Refer to the given number, symbol series and answer the question that follows.
(Left) 3 * @ 5 % 3 + = 3 3 % 8 7 & 5 $ 7 5 & # * 8 2 @ 5(Right)
How many such symbols are there (from left to right) which are immediately preceded by a number and also immediately followed by a number?
1
4
2
5
3
6
4
7