Math worksheet teaching students to calculate the whole from a given percentage using real-world scenarios.

To solve the problems presented in the image, we need to use the relationship between percentages and whole numbers. The general formula to find the whole from a given percentage is:

\[
\text{Whole} = \frac{\text{Part}}{\text{Percentage (in decimal form)}}
\]

Let's solve each problem step by step.

---

Problem 1:

There are 12 students in a classroom wearing green shirts. These 12 students make up 60% of the total students. How many students are in the class in total?

#### Solution:
1. Let the total number of students in the class be \( x \).
2. According to the problem, 12 students represent 60% of the total students.
3. We can write this as:
\[
12 = 0.60 \times x
\]
4. To find \( x \), divide both sides by 0.60:
\[
x = \frac{12}{0.60}
\]
5. Perform the division:
\[
x = 20
\]

#### Answer:
\[
\boxed{20}
\]

---

Problem 2:

2,400 CDs in a store are on sale. These 2,400 CDs make up 80% of the CDs in the store. How many CDs are in the store?

#### Solution:
1. Let the total number of CDs in the store be \( y \).
2. According to the problem, 2,400 CDs represent 80% of the total CDs.
3. We can write this as:
\[
2,400 = 0.80 \times y
\]
4. To find \( y \), divide both sides by 0.80:
\[
y = \frac{2,400}{0.80}
\]
5. Perform the division:
\[
y = 3,000
\]

#### Answer:
\[
\boxed{3000}
\]

---

Problem 3:

A pet store has 15 puppies that have floppy ears. These make up 20% of the total number of puppies in the pet store. How many puppies are there in the pet store?

#### Solution:
1. Let the total number of puppies in the pet store be \( z \).
2. According to the problem, 15 puppies represent 20% of the total puppies.
3. We can write this as:
\[
15 = 0.20 \times z
\]
4. To find \( z \), divide both sides by 0.20:
\[
z = \frac{15}{0.20}
\]
5. Perform the division:
\[
z = 75
\]

#### Answer:
\[
\boxed{75}
\]

---

Problem 4:

A candy shop has 10 employees who are female. They make up 20% of the employee population. How many employees are in the shop?

#### Solution:
1. Let the total number of employees in the shop be \( w \).
2. According to the problem, 10 employees represent 20% of the total employees.
3. We can write this as:
\[
10 = 0.20 \times w
\]
4. To find \( w \), divide both sides by 0.20:
\[
w = \frac{10}{0.20}
\]
5. Perform the division:
\[
w = 50
\]

#### Answer:
\[
\boxed{50}
\]

---

Problem 5:

12 of the students in the school choir are sopranos. These 12 students make up 24% of the choir. How many students are in the choir?

#### Solution:
1. Let the total number of students in the choir be \( v \).
2. According to the problem, 12 students represent 24% of the total students in the choir.
3. We can write this as:
\[
12 = 0.24 \times v
\]
4. To find \( v \), divide both sides by 0.24:
\[
v = \frac{12}{0.24}
\]
5. Perform the division:
\[
v = 50
\]

#### Answer:
\[
\boxed{50}
\]

---

Final Answers:

1. \(\boxed{20}\)
2. \(\boxed{3000}\)
3. \(\boxed{75}\)
4. \(\boxed{50}\)
5. \(\boxed{50}\)