Arithmetic sequence is a sequence with the difference between two consecutive terms constant. The difference is known as the common difference.
Arthmetic Sequence: 2,4,6,8,10,12. The common difference is 2. A pattern of numbers that increase or decrease at a constant amount.
A geometric sequence is a sequence with the ratio between two consecutive terms constant. This ratio is called common ratio.
Geometric Sequence: 2,10,50, 250. 2x5=10 10x5=50 and so on. R=5
A geometric sequence is one where to get from one term to the next you multiply by the same number each time. This number is called the common ration, R.
I hope this helps :)