The expression is
. \ \
\
Place value chart for 17 and
28

Line up the decimal points and draw a line above the numbers.
\Annex zero to align the numbers.
\ \
\
First find the sum of the ones digit.
\The sum of the ones digit =
. \ \

Next find the sum of the tenths digit.
\The sum of the tenths digit =
.

\
\
The sum is
11.