What mass of oxygen is needed for the complete combustion of 4.60×10−3g of methane?

First step in answering the question is to establish a balanced chemical reaction equation. More specifically, a combustion chemical equation. 

CH4 + 2O2 ---> CO2 + 2H20

Then using dimension analysis: 

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later

Sorry i dont understand the question can you rephase it?