Significant Figures

The Basics All nonzero digits are significant

Ex: 1.2 – 2 significant digits Ex: 1.2341 has 5 significant digits

Zeroes between nonzero digits are significant Ex: 1008 has 4 significant digits Ex: 5.007 has 4 significant digits

The Basics Leading zeros to the left of the first nonzero

digits are not significant; such zeroes merely indicate the position of the decimal point Ex: 0.0001 has 1 significant digit Ex: 0.0012 has 2 significant digit

Trailing zeroes that are also to the right of a decimal point in a number are significant Ex: 0.020 has 2 significant digit

The Basics When a number ends in zeroes that are

not to the right of a decimal point, the zeroes are not necessarily significant Ex: 290 may have 2 or 3 significant digits.

Exception to this rule is the use of scientific notation. All digits in the first part of a scientific notated number are significant. Ex: 5.0020 x 106 has 5 significant digits

Exact Numbers Some numbers are known to be exact.

These are often used as conversion factors as discussed yesterday. There are exactly 12 inches in 1 foot. There is exactly 100 cm in 1 meter.

Math Rules When performing a math problem, the

number in the problem with the least amount of significant digits determines the answer. Ex: 5.86 x 21.5482 = 126.272452. This

should be rounded to 3 significant digits, 126.