A device comprising: a communicator configured to communicate with a plurality of wearable devices that are worn on a user's body; and a controller configured to: receive, via the communicator, a plurality of pieces of movement pattern information of the plurality of wearable devices; compare the received plurality of pieces of movement pattern information of the plurality of wearable devices with movement pattern information which is pre-stored in a memory; based on a result of the comparing, determine wearing positions that correspond to each of the received plurality of pieces of movement pattern information for each of the plurality of wearable devices; determine a type of activity performed by the user based on the received plurality of pieces of movement pattern information; determine a main controlled-device that corresponds to the determined activity type of the user for measuring an amount of the activity being performed by the user from among the plurality of wearable devices, based on the determined wearing positions for each of the plurality of wearable devices; and control, via the communicator, the main controlled-device to operate for measuring the amount of the activity being performed by the user, and to control, via the communicator, to turn off the plurality of wearable devices excluding the main controlled-device. a communicator configured to communicate with a plurality of wearable devices that are worn on a user's body; and a controller configured to: receive, via the communicator, a plurality of pieces of movement pattern information of the plurality of wearable devices; compare the received plurality of pieces of movement pattern information of the plurality of wearable devices with movement pattern information which is pre-stored in a memory; based on a result of the comparing, determine wearing positions that correspond to each of the received plurality of pieces of movement pattern information for each of the plurality of wearable devices; determine a type of activity performed by the user based on the received plurality of pieces of movement pattern information; determine a main controlled-device that corresponds to the determined activity type of the user for measuring an amount of the activity being performed by the user from among the plurality of wearable devices, based on the determined wearing positions for each of the plurality of wearable devices; and control, via the communicator, the main controlled-device to operate for measuring the amount of the activity being performed by the user, and to control, via the communicator, to turn off the plurality of wearable devices excluding the main controlled-device. receive, via the communicator, a plurality of pieces of movement pattern information of the plurality of wearable devices; compare the received plurality of pieces of movement pattern information of the plurality of wearable devices with movement pattern information which is pre-stored in a memory; based on a result of the comparing, determine wearing positions that correspond to each of the received plurality of pieces of movement pattern information for each of the plurality of wearable devices; determine a type of activity performed by the user based on the received plurality of pieces of movement pattern information; determine a main controlled-device that corresponds to the determined activity type of the user for measuring an amount of the activity being performed by the user from among the plurality of wearable devices, based on the determined wearing positions for each of the plurality of wearable devices; and control, via the communicator, the main controlled-device to operate for measuring the amount of the activity being performed by the user, and to control, via the communicator, to turn off the plurality of wearable devices excluding the main controlled-device.