Differentiation and Integration
In Calculus, you will learn about integration and also differentiation. Differentiation is usually simpler and more fun for most people. Integration can get complex and difficult to do. But, sometimes, integration is needed and there are many things in life that require the use of integration.
You can get by without but many times proper analysis need the use of integration.
When a function is differentiation, it is well defined with a well defined derivative. If you understand the concept of differentiation, you will not have a problem understanding integration even if you find it hard to do. Practice makes perfect if you want to integrate efficiently.