Significant figures

Significant figures are

counted from left to right starting at the first non-zero digit.

When using scientific

notation, only the first significant figure sits to the left of the

decimal point.

Calculators can be

used to work with scientific notation.

First three significant figures starting from left are 8, 6 and 3

Fourth digit is 5 or more - Round up

so it is 8 640 000

First three significant figures starting from left are 4, 0 and 0

Fourth digit is less than 5 - NO round up

so it is 400 000

First three significant figures starting from left are 5, 6 and 1

Fourth digit is 5 or more - round up the third significant figure

so it is 0.00562

Do not replace digits 8 and 9 with 0's as it will have 5 significant figures then.

38041

0.00521

451000

256010

38041 are 5

0.00521 are 3

451000 are 3, 4, 5 or 6

256010 are 5 or 6.