A method of collaboratively executing a task using first to N-th mobile devices in an ad-hoc network includes determining collaborative mobile devices out of the second to N-th mobile devices, receiving information corresponding to the collaborative mobile devices, dividing the task into first to M-th sub tasks, assigning each of the first to M-th sub tasks to at least one of the collaborative mobile devices, requesting executions of the first to M-th sub tasks to the collaborative mobile devices, and receiving execution results of the first to M-th sub tasks from the collaborative mobile devices. M and N are integers greater than one.