plz provide the correct solution

Q10. [10 pts] Design a Turing machine that takes input a non-negative number x and performs the computable function f(x)=4x. Assume the input is in unary notation, the tape head points in the start of the input. However, you may leave the tape head at any location on the output string when the computation is done. You are also allowed to use the sub programs of INSERT and DELETE. You may assume after INSERT operation, tape head points at the newly added cell while after DELETE operation, tape head points at the same location. An example is given below for your understanding: Status of tape on input is: Status of tape at the output is