Integration is usually taught after differentiation and students find it difficult to understand.

There are two main ways of thinking about integration. In basic terms, the reverse process of Differentiation or the means to finding areas under and between curves.

Definite Integral
is where
we have boundaries
to our integrals. 
Find out more here.

Using Integration
to find
Areas between x-axis and curve
Find out more here.

Using Integration
to find
Areas between curves
Find out more here.

There are methods of Integration rather than lots of rules.

Basic Integration where we have plain letters and nothing too complicated.

Integration by Substitution where we have expressions where before we had only letters.

Integration by Parts where we have divisions or multiplications that cannot be solved by substitution method.

There are many others that you may meet in advanced classes and we will introduce them when we need to see them.
 

Basic Integration

Integration by Substitution

Integration by Parts

Videos Integration by Parts