Simplify to a fraction in lowest terms: \(\frac{\mathrm{6+9} }{\mathrm{6 \times 9}} \)

Perform the addition indicated in the numerator: \(6+9=15\)
Perform the multiplication indicated in the denominator: \(6 \times 9 = 54\)
Present as fraction: \(\frac{\mathrm{15} }{\mathrm{54}}\)
Reduce to lowest terms by dividing: \(\frac{\mathrm{15} }{\mathrm{54}} \div \frac{\mathrm{3} }{\mathrm{3}}=\frac{\mathrm{5} }{\mathrm{18}}\)