In the circuits arrow is shown to give the direction of electric current. They are following the conventional current direction, the direction from +ve to -ve terminal of the battery round the circuit. But electrons flow in the opposite direction which is called electronic current, from -ve to +ve terminal of the battery round teh circuit. The direction of conventional current was defined before the discovery of electrons. However it is not wrong mathematically, because magnitude of the flow of charge in both direction (from +ve to -ve or from -ve to +ve) per unit time is the same.