asterisk. This way the main computation won't look too long or messy and in the event that you are reviewing your notes, after sometime, you could just refer above to the space above guided by the asterisk so that you will be reminded of how you got the value of the interest you used. You could use as many symbols (or letters and others) as needed for any number of computations for value or amount that you would consider better omitted on the main body of your computation. Also it would help that during the discussion in your classroom with your teachers for topics involving computations, you could write it first on a scratch paper like a cheap or low quality band paper and then transfer them in your notebook so it would look cleaner and neater, this would have the advantage of making your notes easier to