Here are the algebraic expressions for each statement:

1. Add up Y and 19
   Expression: $Y + 19$

2. Subtract K from 8
   Expression: $8 - K$

3. Multiply A by 7
   Expression: $7A$

4. Divide x by 3
   Expression: $\frac{x}{3}$

5. $\frac{1}{9}$ of M
   Expression: $\frac{1}{9}M$

6. The product of W and 9
   Expression: $9W$

7. The sum of seven and r
   Expression: $7 + r$

8. Add 3 and then 4 to G
   Expression: $G + 3 + 4$ or $G + 7$

Let me know if you need further clarification or assistance!

Related Questions:

1. Can you simplify any of the above expressions further?
2. What are common scenarios for translating word problems into algebraic expressions?
3. How does the order of operations affect these expressions?
4. Can we visualize these expressions using graphs for variables like $x$ or $y$?
5. How do expressions like $\frac{x}{3}$ behave when $x$ approaches infinity?

Tip:

Always look for keywords like "sum," "product," "difference," and "of" to translate statements into mathematical expressions accurately.