How to insert +-/* and parentheses in the worksheet containing a set of numbers?

Hello. Please help me to write an algorithm insert -+*/ and parentheses worksheet with 4 digits. Found that the possible combinations of insertion of these symbols (brackets not considered yet) will be 3^3(ie there are 3 possible places of insertion mod.digits between 4 digits).
But I can not understand how to cycle, putting the signs in the sheet. I insert only 1 type of character in every possible place, and try all possible values are not obtained. Write in java, rather just learning.
March 19th 20 at 08:46
1 answer
March 19th 20 at 08:48
Just a couple of days ago I had a similar issue - Problem with parentheses)))))))?
And it had some nice ideas you can use

Find more questions by tags Java