hi,

you did not mention which mca entrance test you are going to attempt. most of the entrance exam has maths question from 10+2 syllabus, and as you are a science back ground student you may surely attempt them. mostly questions is done on topic ;ike numerical aptitude, logical reasoning, quantitative ability test etc. rs agarwal books is best to follow for numerical section. there will some computer awareness question which can be easily solved if you have previous years question papers solve. as you are b.sc in computer science you may have learned about hardware and networking of computer perpherals, memory allocation system etc. you may follow the below link to know about mca entrance test:

https://it.careers360.com/articles/5355-7-MCA-entrance-exams