To arrange the numbers 12, 56, 27, and 42 from least to greatest, we will compare each number and position them accordingly.
1. Start by listing the numbers: 12, 56, 27, 42.
2. The smallest number here is 12.
3. Next, we compare 56, 27, and 42. The next smallest number is 27.
4. Now we have 12 and 27. We then look at the remaining numbers, which are 42 and 56. Of the two, 42 is smaller.
5. Thus, the order so far is 12, 27, 42. Finally, the largest number, 56, comes last.
So, the final order from least to greatest is:
12, 27, 42, 56