83.45 rounded to the nearest tenth would be 83.5 because the hundredths place is a number of 5 and above (the number in the hundredths place is 5) which means you move the tenths place value up by 1.
83.45 Tenth is the first number after the decimal. So if the number after the tenth (the hundredths) is 0-4 the tenth doest change. If it's 5-9 you add one to the tenth. Since it is a 5 you add one to the 4 making it 83.5 :)
