Need more practice problems in multi variable functions' and differential equations

We need, especially I need more practice problems in various sectors of multivariable calculus' sectors like in line and surface integrals, flux, green's, stoke's and divergence theorems and all. It would be great if you had quizzes in them too like on other math topics. 

It would have helped greatly if you also include more problems in notes of the above sections,

Also the differential equations sections like second order linear differential equations need more practice problems  And I will be taking linear algebra starting in 2-3 months, it'd be great if it had more practice problems too. 

I do have books to practice problems from but they don't have solutions. So I'm making this request. 

My question is why aren't there any quizzes in any of the above topics I mentioned above? The site was mainly about maths rights, but still seems to math quizzes in the sections mentioned above. 

Please add more problems along with solutions in the form of quizzes, articles etc. 

Sincerely

Ankur