Sure! Let’s go through the sentences in part (a) and identify the mistakes:

1. **We don’t have **much** tomatoes left in the refrigerator.**
- Mistake: **much** (should be **many**)

2. **How many flour does Andy need to make these cakes?**
- Mistake: **flour** (should be **much flour**)

3. **There aren’t **much** butter in the fridge, so we need to buy some.**
- Mistake: **much** (should be **many**)

4. **How **many** glass of water do you drink every day?**
- Mistake: **glass** (should be **glasses**)

5. **Trang adds two **teaspoon** of sugar to the fish sauce.**
- Mistake: **teaspoon** (should be **teaspoons**)

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Now for part (b), completing the questions with "How much" or "How many":

1. **How much** jam do you need?
2. **How much** salt did you put into the soup?
3. **How many** cups of coffee would you like?
4. **How much** sugar is there?
5. **How many** slices of bread are there?
6. **How many** pieces of pizza can you eat?
7. **How much** orange juice is left?
8. **How much** tea is enough for five people?
9. **How many** eggs do you want?
10. **How much** tomato sauce did you buy?

If you have any more questions, feel free to ask!