# What is the difference between summation and integration? [duplicate]

In high school we are studying Integral calculus

Before this we have studied summation which have symbol called 'sigma' $\sum$

Both works similar, sums up the numbers in domain

So my question is what is the difference between the two??

Because I am new to calculus, I don't know too much about calculus.

Another way to think of it is the summation is finding the area under the curve using rectangles of width $dx = 1$. Since the top of each rectangle can't match the angle of the curve, there is some area in the calculation that is actually above the curve. But the integral breaks the area into a nearly infinite number of rectangles, all with a width $dx$ approaching $0$.