types of numbers

• natural numbers


  positive counting numbers represented with the letter N
• integers


  the entire set of whole numbers positive or negative symbolised by Z
• rational numbers

  integers along with recurring and terminating decimals expressed as a fraction with whole numbers as the numerator and denominator represented with the letter Q
• irrational number


  a number that cannot be written as a fraction, terminating, or recurring decimal using the symbol I
• real numbers


  any number that lies on a number line represented as R
• how do you calculate the number of significant figures


  identify the first non zero number, and count all the digits in the number to find the amount
• what is a surd


  When we can't simplify a number to remove a square root (or cube root etc) then it is a surd.