60*【3/5-(1/15+1/4)】
==60*(3/5-19/60)
=60*17/60
=17
1÷(75%+1/4)-1/7
=1÷(0.75+0.25)-1/7
=1÷1-1/7
=1-1/7
=6/7
3/17*5/16+5/17*13/16
=(5/16+13/16)*(3/17+5/17)
=18/16*8/17
=9/17
60*【3/5-(1/15+1/4)】
==60*(3/5-19/60)
=60*17/60
=17
1÷(75%+1/4)-1/7
=1÷(0.75+0.25)-1/7
=1÷1-1/7
=1-1/7
=6/7
3/17*5/16+5/17*13/16
=(5/16+13/16)*(3/17+5/17)
=18/16*8/17
=9/17