“Abracadabra, make two more pennies appear!” my daughter said as she shifted the paper plates to magically show three pennies total on the table. Money appearing from thin air is everyone’s dream, and ...

Forget the traditional, cumbersome method and use this trick: to multiply a number by 5, divide by 2, and move the decimal point one decimal place to the right. SO, if, say, you had the number 8,600 ...