  The variation procedure on a teleparallel manifold is studied. The main
problem is the non-commutativity of the variation with the Hodge dual map. We
establish certain useful formulas for variations and restate the master formula
due to Hehl and his collaborates. Our approach is different and sometimes
easier for applications. By introducing the technique of the variational matrix
we find necessary and sufficient conditions for commutativity
(anti-commutativity) of the variation derivative with the Hodge dual operator.
A general formula for the variation of the quadratic-type expression is
obtained. The described variational technique are used in two viable field
theories: the electro-magnetic Lagrangian on a curved manifold and the Rumpf
Lagrangian of the translation invariant gravity.
