don't be stupid..........you cannot explain it indeed:
the only reasons for low grades in 几门数学 is the student is poor in mathematics. that's it.
no matter what you say or explain, those are just excuse or treated as empty words.
if the program has a high maths requirement, you are out.
if the program don't care about it, why explain it in PS then?
1. what's the point of getting better quantitative skills? does this help in your further career goal indeed?
2. well....given you want more quantitative education, you need a more quantitative economics master, so.......umum, what make you confident that you can handle it without a good mathematics background?