Hi. I want to become a warehouse manager. I got degree of BSc. In science. Math. What should I study?

First of all, you are a graduated in Science, This qualification is enough to start your career and find a job where your desire could be fulfill I am sure you will get a job in WH management  of any kind Industry. same time you could pursue certification course like in Supply chain Procurement & Logistics off course Material Management course will also helpful to you where its involve Inventory Management WH management etc. These  courses are available Online, Correspondences and Part time, e.g check with APICS USA for Supply chain Management & CIPS for Procurement & Supply on the Internet. 

Hi, you could do a diploma in Logistics and supply chain management. Since you have completed your bachelors, you could go for a post graduate diploma.

This is only a suggestion.