Final answer:
The lowest common multiple of 10 and 20 is 20, which is the smallest number that is a multiple of both.
Step-by-step explanation:
The lowest common multiple (LCM) of two numbers is the smallest number that is a multiple of both. To find the LCM of 10 and 20, we should list the multiples of each number until we find a common one:
- 10: 10, 20, 30, 40, ...
- 20: 20, 40, 60, 80, ...
It's clear that the first common multiple of 10 and 20 is 20. Therefore, the LCM of 10 and 20 is 20.
Example of finding the LCM:
- List the first few multiples of each number. 10: 10, 20, 30, 40 ... 20: 20, 40, 60, 80 ...
- Identify the smallest number that appears in both lists, which is 20.