It's true—you CAN do simple everyday math in your head, without a calculator! Improve your mental math skills in one week with just ten minutes of practice a day. Join The Math Dude, Jason Marshall, as he leads you through the tricky journey of mastering addition, subtraction, multiplication, division, AND percentages in your head. Whether you're calculating the tip on a $76.85 meal or you're frantically doing mental math in a business meeting—Math Dude has got you covered.