To round the number 12.56 to the nearest tenth, we look at the digit in the hundredths place, which is the second digit to the right of the decimal point.
In 12.56, the tenths place is occupied by 5 (the first digit after the decimal), and the hundredths place has a 6. Since the digit in the hundredths place (6) is 5 or greater, we round up the tenths place digit (5) by 1.
This means we add 1 to the 5 in the tenths place, making it 6. Therefore, 12.56 rounded to the nearest tenth is 12.6.