Advent Puzzles 2014: puzzle 20 solution

Advent puzzle 20: Use all of 20, 40, 60, and 80, with any of +− ×÷(), to make all totals from 1 to 10. One total can't be made. Which one?

— Portsmouth MathsJam (@MathsJamPOR) December 20, 2014

Most numbers have several solutions. One solution for each possible total is given below.

$1=(20+80)\div(40+60)$
$2=(20+60)\div(80-40)$
$3=(20+40)\div(80-60)$
$4=(20+60+80)\div40$
$5=(80\div40)+(60\div20)$
$6=(80\div40)\times(60\div20)$
$7=(60+80)\div(40-20)$
$8\mbox{ cannot be made.}$
$9=(40+60+80)\div20$
$10=(80-60)\div(40\div20)$