May 21 (UPI) --An 11-year-old Florida girl earned a Guinness World Record for mental math when she solved a 12-digit multiplication problem without a calculator, pen or paper. Sanaa Hiremath, who was ...
After duplex numbers, let us learn multiplication by triplex numbers. As the name suggests, numbers like 111, 222, 333 are triplex numbers. The method is similar to that of multiplication by duplex ...