How is one molecule of atp formed from one molecule of adp

Statement from Biology-Online.org; it states, "ATP to ADP - Energy Release. This is done by a simple process, in which one of the phosphate molecules is broken off, therefore reducing the ATP from 3 phosphates to 2, forming ADP"

In simpler words, ATP is a more powerful molecule containing 3 phosphates, while they will go into a cycle (I forgot the name), where phosphates are kicked out, therefore the ATP now has 2 phosphates, THUS TURNING INTO ADP. Since it had 2 phosphates, it is no longer classified as ATP, it is classified as ADP.

A phosphate is added in some way shape or form. ATP stands for adenosine tri phosphate and ADP stands for adenosine di phosphate. The phosphate is added to the ADP to make it ATP