|
A running total is the summation of a sequence of numbers which is updated each time a new number is added to the sequence, by adding the value of the new number to the previous running total. Another term for it is partial sum. The purposes of a running total are twofold. First, it allows the total to be stated at any point in time without having to sum the entire sequence each time. Second, it can save having to record the sequence itself, if the particular numbers are not individually important. ==Method== Consider the sequence < 5 8 3 2 >. What is the total of this sequence? Answer: 5 + 8 + 3 + 2 = 18. This is arrived at by simple summation of the sequence. Now we insert the number 6 at the end of the sequence to get < 5 8 3 2 6 >. What is the total of that sequence? Answer: 5 + 8 + 3 + 2 + 6 = 24. This is arrived at by simple summation of the sequence. ''But'' if we regarded 18 as the running total, we need only add 6 to 18 to get 24. So, 18 was, and 24 now is, the running total. In fact, we would not even need to know the sequence at all, but simply add 6 to 18 to get the new running total; as each new number is added, we get a new running total. The same method will also work with subtraction, but in that case it is not strictly speaking a total (which implies summation) but a running difference; not to be confused with a delta. This is used, for example, when scoring the game of darts. Similarly one can multiply instead of add to get the running product. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Running total」の詳細全文を読む スポンサード リンク
|