Final answer:
You should wash your hands for at least 20 seconds, making sure to wash all areas including the thumbs, wrists, areas between the fingers, and under the nails.
Step-by-step explanation:
According to the CDC, you should wash your hands for at least 20 seconds. Wet your hands with clean, running water, then apply soap and rub your hands together for 20 seconds, making sure to wash all areas including the thumbs, wrists, areas between the fingers, and under the nails. To keep track of the time, you can hum the 'Happy Birthday' song twice.