The question asks to identify which statement about the multiples of 21 is true. Let's analyze each option:

1. 21 is a multiple of 6:

   • To check, divide 21 by 6: $21 \div 6 = 3.5$. Since the result is not an integer, 21 is not a multiple of 6.

2. 21 is a multiple of 5:

   • To check, divide 21 by 5: $21 \div 5 = 4.2$. The result is not an integer, so 21 is not a multiple of 5.

3. 21 is a multiple of 4:

   • To check, divide 21 by 4: $21 \div 4 = 5.25$. Since the result is not an integer, 21 is not a multiple of 4.

4. 21 is a multiple of 3:

   • To check, divide 21 by 3: $21 \div 3 = 7$. The result is an integer, so 21 is a multiple of 3.

Correct Answer:

21 is a multiple of 3.

Would you like further explanation or a deeper dive into multiples?

Related Questions:

1. What is the definition of a multiple?
2. How do you identify if a number is a multiple of another?
3. What are some other multiples of 3 besides 21?
4. Why isn't 21 a multiple of 6, 5, or 4?
5. Can 21 be expressed as the product of other numbers besides 3 and 7?

Tip:

Always ensure to check for divisibility by dividing the number by the potential multiple and confirming the result is an integer!