1997- $3.38
Rounding to the nearest tenth of a dollar would be rounding to the first number after the decimal point (the tenths place), and the number(s) after that would be zero.
$3.38 rounds up because the digit after the tenths place is 8, which is more than 5, so the final answer is $3.40.
198- $2.65
This one is trickier because your number ends with a 5 in the hundredths place. However, most math books would want you to round up when you have a 5, so the final answer is $2.70.