Significant Figures (Significant digits)

The term “significant figures” refers to the digits, in a number or measurement, which show the accuracy of the number.

Refer to wiki: Significant figures
Refer to Khan academy: Intro to significant figures

Rules of Significant figures

Concise Rules:

• All non-zero digits are significant: 1, 2, 3, 4, 5, 6, 7, 8, 9.
• Zeros between non-zero digits are significant: 102, 2005, 50009.
• Leading zeros are NEVER significant: 0.02, 001.887, 0.000515.
• In a number with a decimal point, trailing zeros (those to the right of the last non-zero digit) are significant: 2.02000, 5.400, 57.5400.
• In a number without a decimal point, trailing zeros may or may not be significant. More information through additional graphical symbols or explicit information on errors is needed to clarify the significance of trailing zeros.