There are over 6 billion people in the world, and the vast majority of them belong to a religion of some type. Of these 6 billion people, about 2 billion of them are Christians. After Christianity, the next seven largest religions are Islam, Hinduism, Buddhism, Animism/Paganism, Judaism, Confuciansim, and Daoism. Similarities and differences exist among Judaism, Christianity, Animism/Paganism, Islam, Buddhism, Hinduism, Confucianism, and Daoism, however the greatest similarities can be seen with Buddhism and Hinduism, and the greatest differences can be seen with Christianity, Hinduism, and Animism/Paganism.
Judaism, Christianity, and Islam are very similar. They are all monotheistic, and much of their religion is centered around that religion's god. Whether it is the Christian God, Islam's Allah, or Judaism's Jahweh, each of these religions believe their god is the only god, and that there can be no other god. Each of these religions has their own holy book, the Christianity has it's bible, Judaism has Jewish Bible, or Tenakh, and the Islam faith has the Qur"an. Each of these religions is well represented, with Judaism having at least 12 million followers, Islam having at least a billion, and Christianity having over 2 billion. Each of these religions also has their on prophet. Muslims believe there were many prophets, including Mohammad, the last prophet. The Judaism prophet was Moses, who could also be considered a prophet by Christians as well.
Though Judaism, Christianity, and Islam are quite similar, they have their differences as well. Followers for the different religions worship differently. Christians worship at church, generally on Sundays, but have no set amount of worshipping that must me done. Jewish people on the other hand, are supposed to pray three times a day, and Muslims are supposed to pray five times. Muslims have the strictest form of worship. More conservative Jews take off their shoes before entering a mosque to pray, and then perform a strict cleansing ritual, in which they clean their hands, face, and feet several times.