Supernumerary robotic limbs may one day allow people to perform tasks as if they had an extra limb, extending human capabilities. One challenge with supernumerary robotic limbs is how to control them. One method is teleoperation using the foot. This allows a person to continue using their arms. However, it is not clearly known how well a person can physically and cognitively use a foot-controlled supernumerary robotic arm and both of their arms simultaneously. We present an experiment that shows that using the foot to control a supernumerary robotic arm improves task performance. The task was selected so that it could be performed using only two hands, where the hands switch between subtasks. The use of only two hands provides a baseline for comparison. The results show that using the foot with the hands improved performance relative to just using the hands alone.