Lesson 3 of 11·4 min

Totals, balances and currency: avoiding misleading arithmetic

Not every numeric field should be added. Transaction amounts can often be totalled when their meaning and currency are consistent. A running balance already includes earlier movements, so adding successive balances usually counts the same history repeatedly.

Suppose a balance progresses from USD 100 to USD 150 and then USD 130. The ending balance is USD 130. The sum USD 380 is not another valid ending balance. The required calculation depends on the business question.

Aggregation in DNA

DNA's reporting supports grouped results, subtotals, grand totals and configured summary calculations. The report viewer also handles statement-specific measures and combined totals. A profit result, for example, may be a calculated combination of categories rather than a simple sum of every visible number.

The flat-report chart path uses an aggregation helper and handles appended total rows and running-balance fields. These controls address specific reporting problems, but they do not remove the need to understand the chosen fields.

Currency consistency

Amounts in different transaction currencies cannot be added meaningfully merely because they appear in one column. Use a common reporting basis or keep currency totals separate. For a fictional comparison expressed entirely in USD, USD 800 plus USD 200 is USD 1,000; that arithmetic assumes both values already have the same currency meaning.

DNA's viewer uses currency metadata and base-currency counterpart fields when available for combined reporting measures. Check the actual field and currency basis. A symbol in a heading alone is not evidence that conversion occurred correctly.

Averages and ratios

An average of averages can be misleading when groups differ in size. One group averaging USD 100 across two records and another averaging USD 200 across eight records have a combined weighted average of USD 180, not USD 150.

Likewise, a percentage needs a defined denominator. A customer's share of selected sales differs from its share of all company sales. Explain the numerator, denominator and scope before drawing a conclusion from a ratio or summary row.

Check your understanding

Not marked. Answer every question to finish the lesson.

Question 1 · Choose one answerConsider this statement about totals, balances and currency: Adding all opening, movement and closing balances always produces a meaningful total. Is the statement correct?

TrueFalse

Question 2 · Choose one answerCheck your understanding of totals, balances and currency: Which statement is accurate?

Mixed-currency amounts require a consistent conversion basis before aggregation.Any displayed total can be compared directly with any other report total.Adding all opening, movement and closing balances always produces a meaningful total.

Question 3 · Choose every answer that appliesCheck your understanding of totals, balances and currency: Select all correct statements. Exactly two answers are correct.

Any displayed total can be compared directly with any other report total.Balances and period movements must not be summed as if they were identical measures.Mixed-currency amounts require a consistent conversion basis before aggregation.Adding all opening, movement and closing balances always produces a meaningful total.

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