On Saturday, the Bleecker Area Merchants’ and Residents’ Association (BAMRA) sponsored a free “Learn To Ride a Bicycle” event at Mercer Playground to teach kids ready for a two-wheeler how to balance and ride. Trainers from Bike New York were on hand at the park, on Mercer St. between Bleecker and W. Third Sts., from noon to 2 p.m., and helped instruct more than 20 tykes on the essentials of riding a bike. Terri Cude, the event’s main organizer, was happy to report that a bunch of the children who had never ridden on two wheels before learned how to bicycle in just one session.