1. The problem is to understand and apply the concept of three significant figures in numerical values. 2. Significant figures are the digits in a number that contribute to its precision. This includes all non-zero digits, any zeros between them, and trailing zeros in the decimal part. 3. To round a number to three significant figures, identify the first three digits starting from the left (ignoring leading zeros), then round the third digit based on the digit following it. 4. For example, to round 0.0045678 to three significant figures: - The first three significant digits are 4, 5, and 6. - The next digit is 7, which is greater than 5, so we round up the 6 to 7. - The rounded number is 0.00457. 5. Another example: rounding 12345 to three significant figures: - The first three digits are 1, 2, and 3. - The next digit is 4, which is less than 5, so we keep 3 as is. - The rounded number is 12300. 6. Remember, when rounding, if the digit after the last significant figure is 5 or more, round up; if less than 5, round down. 7. This method helps maintain the precision of measurements and calculations in scientific and engineering contexts.