His funny thought

This two days Ethan have been playing with grandfather "万步机". He has hooked it on his pants and ran about in order to know how many steps that he had walked. He saw the number kept on increasing when he walked with it. He was wondering whether the machine can reduce the number or not. Since he knows that walk forward can increase the number so he tried to walk backward and hoped that the number of steps can be reduced. We were laughing at his action and his thinking.....