Question

Hello Rabbi,
I wanted to ask whether the separation formula below is correct from a halakhic standpoint.
I’m asking because I think I understand how terumot and ma'asrot work, but I never manage to understand the logic of the formula that appears in prayer books, which in my opinion is really not clear. So if this is correct, I could say this instead:

If this produce is fourth-year produce, then its value plus another 25% of its value is redeemed onto a perutah's worth from the coin in my possession.

And if it is not, and it is obligated in terumot and ma'asrot,
he should separate a little more than one percent of the produce and say:
The part in excess of that one percent which I separated is terumah gedolah, for which there is no fixed measure.
That one percent which I separated, together with another nine percent from the area located at the beginning of the vegetables' growth, shall constitute first tithe.
The separated one percent, which is adjacent to the terumah, shall be the tithe of the tithe.
 
If the produce is obligated in second tithe or the poor man's tithe, then ten percent from the areas of the produce that are not connected to terumah gedolah or the first tithe shall be second tithe or the poor man's tithe, on the side close to the area of the end of the fruit's growth, according to the obligation of that produce.
And if it is obligated in second tithe, then its value plus another 25% of its value is redeemed onto a perutah's worth from the coin in my possession.