1.3.3　Scientific notation

As the digit of the significant figures of the approximate value is related to the magnitude of the error,the digit will not change when the unit changes.For example,0.027 3 m can be written as 2.73 cm or 0.000 027 3 km.They both are 3-digit significant figures with a doubtful figure in the last digit.However,the approximation can not be written as 27 300 μm because it is a 5-digit significant figure.Instead,it should be written as 2.73×104 μm as the scientific notation.The proper format for scientific notation is(a times 10 to the power of b)to put a as a number or decimal number which conform to,and b is the power of 10 required so that the scientific notation is mathematically equivalent to the original number.(https://www.daowen.com)