## Practice questions

- Twenty-four is the least common multiple of 8 and which of the following numbers?
**A.**12**B.**36**C.**4**D.**16**E.**2 - What is half the square of the least common multiple of 14 and 21?
**A.**882**B.**98**C.**1,764**D.**220.5**E.**196

## Answers and explanations

- The correct answer is Choice
**(A).**Twenty-four is a multiple of only Choices (A), (C), and (E). You can list the first few multiples of those choices and 8 to determine the answer to the question. Here are the multiples of 8 and Choice (A):

**Multiples of 8:**8, 16, 24 …**Multiples of 12:**12, 24, … Without going any further, you can see that 24 is the least common multiple of 8 and 12, so Choice (A) is correct. In case you're curious, 8, not 24, is the least common multiple of 8 and Choices (C) and (E). - The correct answer is Choice
**(A).**Add each number to itself multiple times to find its first few multiples:

**Multiples of 14:**14, 28, 42, 56, 60, 74, …**Multiples of 21:**21, 42, … You can see that 42 is the least common multiple of 14 and 21. The square of 42 is 42^{2}, which is42 × 42

or 1,764. That number divided by 2, or times 1/2, is 882.