Concept:
When rounding numbers to a specified number of decimal places, standard scientific rounding rules (often called the round-to-nearest-even rule or bankers' rounding) apply to eliminate rounding bias when the digit to be dropped is exactly 5.
Rules for rounding when the trailing digit is exactly 5:
• Identify the last digit to be retained (the target place).
• Look at the digit immediately following it. If that next digit is exactly \(5\) (with no non-zero digits following it):
itemize
• If the digit to be retained is
even, leave it unchanged.
• If the digit to be retained is
odd, increase it by \(1\) to make it even.
itemize
Step 1: Rounding the value \(17.0145\)
We want to round to three figures after the decimal point.
• The third digit after the decimal point is
\(4\).
• The digit immediately following it is
\(5\).
• We examine the value of our target third decimal digit: \(4\) is an
even number.
• Applying the rule for an even preceding digit, we leave it unchanged.
• Result: \(17.014\)
Step 2: Rounding the value \(21.0235\)
We want to round to three figures after the decimal point.
• The third digit after the decimal point is
\(3\).
• The digit immediately following it is
\(5\).
• We examine the value of our target third decimal digit: \(3\) is an
odd number.
• Applying the rule for an odd preceding digit, we increase it by 1 to make it even (\(3 + 1 = 4\)).
• Result: \(21.024\)
Combining our calculations, the rounded values are \(17.014\) and \(21.024\).