Final answer:
One 100 milligram allopurinol tablet should be administered to match the doctor's prescription of 0.1 grams.
Step-by-step explanation:
The doctor has prescribed allopurinol 0.1 gram tablets by mouth, and you need to determine how many 100 milligram tablets should be administered. To convert grams to milligrams, you must know that 1 gram equals 1000 milligrams. Thus, 0.1 gram is equal to 0.1 × 1000 milligrams, which is 100 milligrams. Since the tablets available are 100 milligrams each, you would administer one tablet to equal the 0.1 gram dose that the doctor ordered.