To find the total quantity of liquid ingredients, we need to sum the amounts of milk and oil, as specified in the problem.

From the image:

• Milk: $\frac{1}{4}$ cup
• Oil: $\frac{3}{8}$ cup

Step-by-step addition of fractions:

1. To add $\frac{1}{4}$ and $\frac{3}{8}$, we first need a common denominator.
2. The least common denominator (LCD) between 4 and 8 is 8.
   • Convert $\frac{1}{4}$ to have a denominator of 8:
     $\frac{1}{4} = \frac{2}{8}$
3. Now add the fractions:
   $\frac{2}{8} + \frac{3}{8} = \frac{5}{8}$

So, the total quantity of liquid ingredients is $\frac{5}{8}$ cup.

Would you like more details or have any questions?

Relative Questions:

1. How do you convert fractions with different denominators to have a common one?
2. Can you explain why the least common denominator is important in fraction addition?
3. What are the steps to simplify fractions after addition?
4. How would you approach subtraction of liquid ingredients if one is removed from the recipe?
5. Could you mix improper fractions with mixed numbers and still find the total amount?

Tip:

When adding fractions, always ensure they have a common denominator before performing the operation to avoid errors.