I see why algorithmic thinking might be important for a developer position, but I agree that mathematical problems are not the best way to test for that. Designing a flow of form data with some validation in a UI component is an equally plausible exercise in algorithmic thinking and far more useful engineering skill than an asterisk Christmas tree. I always found those mathematical problems convoluted and detached from reality of modern-day development, and they do not differentiate between the abilities, traits and skills that form a foundation and those that can be acquired on the job. Hiring a person that can speak formulas doesn’t ensure that this person will be able to communicate with the rest of the team, which will probably be worse than an extra hour they would spend on building a Christmas tree. Practical experience working in projects that solve real-world problem is far more interesting than the ability to remember language syntax and building a tree with minimum iterations on first try under time and peer pressure.