9/42X7/13+3/5=3/26十3/5=93/130
9/42*7/13+3/5=(9*7)/(42*13)+3/5=3/26+3/5=(3*5+3*26)/(26*5)=91/130
9/42×7/13+3/5=3/2×1/13+3/5=3/26+3/5=3×(1/26+1/5)=3×(5/130+26/130)=93/130
9/42 * 7/13 +3/5=9/(6*13) +3/5=3/26+3/5=15/130+78/130=93/130