Let's work through the problems on your image, where you're dividing whole numbers by fractions.

Key Concept:

Dividing by a fraction is the same as multiplying by its reciprocal. For example: $\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c}$ So for each problem, we will multiply the whole number by the reciprocal of the fraction.

Solving each one:

1. $24 \div \frac{3}{8}$

   • Reciprocal of $\frac{3}{8}$ is $\frac{8}{3}$.
   • So, $24 \times \frac{8}{3} = \frac{24 \times 8}{3} = \frac{192}{3} = 64$.

2. $98 \div \frac{7}{21}$

   • Reciprocal of $\frac{7}{21}$ is $\frac{21}{7}$.
   • So, $98 \times \frac{21}{7} = \frac{98 \times 21}{7} = \frac{2058}{7} = 294$.

3. $19 \div \frac{1}{5}$

   • Reciprocal of $\frac{1}{5}$ is $5$.
   • So, $19 \times 5 = 95$.

4. $35 \div \frac{1}{5}$

   • Reciprocal of $\frac{1}{5}$ is $5$.
   • So, $35 \times 5 = 175$.

5. $80 \div \frac{2}{8}$

   • Reciprocal of $\frac{2}{8}$ is $\frac{8}{2} = 4$.
   • So, $80 \times 4 = 320$.

Answers:

1. $64$
2. $294$
3. $95$
4. $175$
5. $320$

Would you like more details on any of these steps, or do you have any questions?

Here are five related questions for further practice:

1. How do you multiply a fraction by a whole number?
2. What is the general rule for dividing by fractions?
3. How can you simplify fractions before dividing or multiplying?
4. What is the reciprocal of a mixed number?
5. How do you convert improper fractions to mixed numbers after multiplying?

Tip: When dividing by fractions, always remember to multiply by the reciprocal of the fraction.