The Jews believe in one God.
The Christians believe that Jesus is the son of God.
The Muslims believe there is one God and Muhammed is his prophet.
None of the above mentioned religions believes the other two are correct. So they can't all be worshiping the same supernatural being. - Tom
Your logic is flawed. It is entirely possible for these three religions to be worshiping the same God while doing so in different ways, recognizing different prophets, believing in different texts, etc.