Final answer:
The numbers 8.15, 8.04, and 8.009 should be ordered from least to greatest by comparing them digit by digit after the decimal. The correct order is 8.009, 8.04, 8.15, which is option a).
Step-by-step explanation:
To order the numbers 8.15, 8.04, and 8.009 from least to greatest, we compare them digit by digit. The first digit in all numbers is 8, which is the same, so we look at the next digit.
The second digit after the decimal in 8.04 is 0, in 8.15 is 1, and in 8.009 is 0. At this stage, 8.04 and 8.009 are potential candidates for the smallest number, but 8.04 has a 4 in the third position, while 8.009 only has a 0. This means that 8.009 is the smallest number.
Comparing 8.04 and 8.15 next, we see that 8.04 has a 0 in the second position, while 8.15 has a 1. Therefore, 8.04 must be the second smallest number, and 8.15 is the greatest.
The correct order from least to greatest is 8.009, 8.04, 8.15.
The option that matches this order is: a) 8.009, 8.04, 8.15.