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Rounding Off - Definition, Rules, Examples

... length measured, etc are estimated by rounding off the actual number to the ... Rounding off numbers is done to preserve the significant figures. ... Rounding rules for decimal numbers are as follows: ... Since the digit in the smallest place is less than 5, round down has to be done ... time definition physics · standard units.

For more information, see Rounding Off - Definition, Rules, Examples

Significant digits or significant figures are the reliable digits plus the first uncertain digit.

The rules for calculating the number of significant figures

• All of the non-zero digits are significant.
• All zeros between two non-zero digits are significant, regardless of where the decimal point is, if it exists at all.
• A change in units has no impact on the number of significant digits or figures in a measurement.
• The preceding or trailing zero(s) in a number without a decimal point are insignificant.
• In a number with a decimal point, the trailing zero(s) are significant.
• If the number is less than one, the zero(s) to the right of the decimal point but to the left of the first non-zero digit are not significant.

a) 0.007 m^2

  Significant figures = 1

b) 2.64* 10^{24} kg

Significant figures = 3

c) 0.2370 gcm^{-3}   

Significant figures = 4

d) 6.230 J

Significant figures = 4

e) 6.032 Nm^{-2}

Significant figures = 4

f) 0.0006032 m^2

Significant figures = 4