Which budgeting method takes a bottom-up approach by defining specific objectives, determining the tasks needed to achieve these objectives and then estimating how much each task will cost?

The bottom-up budgeting is a budgeting method where individual departments or business units prepare their own budgets and them send it upwards (to upper management) for approval or modifications.

The main advantage of this budgeting method is that the focus is set on each department's objectives instead of a predetermined amount set by upper management.