if you are in class 6th you might be knowing about Pythagoras theorem , you can write about the mathematician Pythagoras or you can go the easy way by writing about Aryabhatta and Ramanunjan , they will be great... you might know that what was the dicovery of Aryabhatta , if you don't alas , its ZERO , you can do a research on them on wiki pedia and come up with your own innovative ideas proving the Pythagorean theorem works .... that's all i can suggest .....
BEST OF LUCK
