Modify the Thread Operation

Question

How can we modify the thread operation by using another thread.like i want to change the label text which is updating in a thread operation,bur i want to change the text of label by another thread without disturbing the original operation.for example in first thread label text incremented by one and when it reaches to 9 it again becomes 0,but when i run my second thread i want to increment the label text by 2 and maximum range is 100.Thanks