RATIO - Ratio of two terms 'a' and 'b' is denoted as a:b (read as 'a is to b') and it is measured by a/b. - The ratio cannot be formed until the numbers are expressed in the same units. - A ratio compares two numbers. - Ratio remains unaltered when neumerator and denominator are multiplied or divided by same number. e.g., a:b = a/b = (a*m)/(b*m) = (a/m)/(b/m)