Arithmetic Progressions is a sequence of number thats arrange in specific order according to some rules.
numbers occurring in a sequence are called its terms.
mainly terms of sequence denoted by a1,a2,a3,a4,...etc. where a1 is a first term of sequence ,a2 is a second term of sequence and an is nth term of sequence .
in arithmetic progression difference between 1st term and 2nd term are same as different between 2nd term and 3rd term or nth term and (n-1)th term. these different called as a common difference of arithmetic progressions.
in this sequence
2 is 1st term
5 is 2nd term
and so on..