The value of the "6" in the thickness of a penny is 6 hundredths. The second digit after the decimal point is called the hundredths place. It tells us how many hundredths there are in the number.
In our case the number (the thickness of the penny) is 0.061. The value of 6 is on the second place after the decimal point, which means that the value of the "6" is 6 hundredths.