Question 1140339
The expression is ambiguous.  As a guess, it might be intended as {{{(3/5-1/4)(2&1/7)}}}.


{{{(12/20-5/20)(15/7)}}}

{{{(7/20)(15/7)}}}

{{{15/20}}}

{{{highlight(3/4)}}}









---not this:
{{{cross((15/20)(15/7))}}}

{{{cross((3/4)(15/7))}}}

{{{cross(45/28)}}}
or as mixed number,
{{{cross(1&17/28)}}}