Enlarge Image Primed for numbers. Random pulses of electrical current can accelerate math learning. Credit: Albert Snowball If you are one of the 20% of healthy adults who struggle with basic arithmetic, simple tasks like splitting the dinner bill can be excruciating. Now, a new study suggests that a gentle, painless electrical current applied to the brain can boost math performance for up to 6 months. Researchers don't fully understand how it works, however, and there could be side effects. The idea of using electrical current to alter brain activity is nothing new—electroshock therapy, which induces seizures for therapeutic...