AP PSYCHOLOGY

Detailed explanation-1: -We round a number to three significant figures in the same way that we would round to three decimal places. We count from the first non-zero digit for three digits. We then round the last digit. We fill in any remaining places to the right of the decimal point with zeros.

Detailed explanation-2: -The number 450 has two significant figures and would be written in scientific notation as 4.5 × 102, whereas 450.0 has four significant figures and would be written as 4.500 × 102.

Detailed explanation-3: -39, 004 has five significant figures. 5.02 has three significant figures.

Detailed explanation-4: -The quantities 306, 30.6, 3.06 and 0.306 all contain 3 significant figures since the 0 between the 3 and 6 is significant. The number 306 means that the true value rests somewhere between 305 and 307, thus, the zero is known with certainty and is significant. That is, zeros within a number are always significant.