Identify the initial amount
Find the time interval
Determine the amount remaining after each interval
Use the formula: remaining amount = initial amount × (1/2)^(time ÷ half-life)
Solve for the half-life if the remaining amount and time are known
Rearrange the formula: half-life = time ÷ log2(initial amount ÷ remaining amount)
Check that the time and amount units match
Verify the result by confirming the amount halves in each half-life interval