Question: Is carbohydrates and starch the same thing ?? if not what is their relationship ?  Edit

Answer: large group of organic compounds, including sugars, such as sucrose, and polysaccharides, such as cellulose, glycogen, and starch, that contain carbon, hydrogen, and oxygen, with the general formula Cm(H2O)n are called Carbohydrate.

Starch is a complex carbohydrates and its a polysaccharide means on hydrolysis, starch will produce so many numbers of monosaccharides. Starch is also called as Non Sugar.

the chemical formula of Starch is (C6H10O5)n

So all starchs are carbohydrate but all carbohydrate are not starch. Starch is a particular type of Carbohydrate.  Edit