If for example you have to write a taweez of 787. So after you deduct 30 from this sum you ill get 757. When you divide 757 by 4 you will get 189 and the remainder will be 1. This remainder will be added to the box number 13 to complete the taweez.
This is an Atishe methodology taweez and by adding 1 to its 13th box I have completed it.
Remember me in your prayers,