1. The problem is to simplify the expression $\frac{a}{b}1 3 + 6$.\n\n2. First, clarify the expression. It seems to be $\frac{a}{b} \times 1 \times 3 + 6$.\n\n3. Use the multiplication rule: $\frac{a}{b} \times 1 = \frac{a}{b}$.\n\n4. Then multiply by 3: $$\frac{a}{b} \times 3 = \frac{3a}{b}.$$\n\n5. Now add 6: $$\frac{3a}{b} + 6.$$\n\n6. To add these, write 6 as a fraction with denominator $b$: $$6 = \frac{6b}{b}.$$\n\n7. So, $$\frac{3a}{b} + \frac{6b}{b} = \frac{3a + 6b}{b}.$$\n\n8. Factor the numerator: $$\frac{3a + 6b}{b} = \frac{3(a + 2b)}{b}.$$\n\n9. Final simplified expression is $$\frac{3(a + 2b)}{b}.$$