1. An X-ray apparatus comprising: an input interface configured to receive a first user input for setting an imaging area of an object; a controller configured to divide the set imaging area into a plurality of partial X-ray imaging regions and determine an order of imaging operations for the plurality of partial X-ray imaging regions based on size information about portions of the object respectively represented on the plurality of partial X-ray imaging regions; and an X-ray radiator configured to radiate X-rays onto the plurality of partial X-ray imaging regions according to the determined order of imaging operations to perform partial imaging of the object.