The expression is 

Place value chart for 73.98 and 5.16.

Line up the decimal points and draw a line below the numbers.

 First find the difference of the hundredths digit.

The difference of the hundredths digit, .

 First find the difference of the tenths digit.

The difference of the tenths digit, .

 First find the difference of the ones digit.

The difference of the ones digit, 3 is lesser than 5 so borrow 1 from tents digit. .

Next in tens digit only 6 is left. \ \

The difference of is 68.82.