Significant figures definition

Significant figures
The specified number of digits which are accepted to denote the approximate value of the number which is expressed as an integer and a decimal number. For example a distance of 984325 km. It can be taken as 984300 km which is correct to four significant digits, the last two zeros are not significant as they denote the order of magnitude only. Similarly, the number of significant digits in 0.00678 is 3, as the zeros, in the beginning, are used to denote the value of the place of the digits. Thus the zeros at the end of a whole number or decimal may or may not be significant according to the degrees of accuracy required but zero on the left is never the first significant figure.
Similar figures
Geometrical figures which have the same shapes but different sizes. More precisely, two or more figures are said to be similar if a mapping can be defined between them such that the ratio of the distance between pairs of points of one figure remains the same for the corresponding point of the other figure.

Similar fraction
A fraction
having the same denominators.
For example 4/9,5/9 and respectively 0.444444 and 0.555555
Similar terms
Like terms, terms are expressions that differ in their coefficient only. Similarly, terms can always be combined into a single term. For example 8xy^2z,+6xy^2z are like terms and hence combining to give a single term 14xy^2z