Great question! It depends on how hard you want to compete.Even if someone tells you that yes,you can qualify the exam with little effort and it is an easy exam..The harsh reality is that it is you who has to take the exam and probably have to work harder than others (in case you are not average but weak in mathematics). I am not going to suggest you a strategy or some short tricks but what you should really do . Buckle-up first,you have nothing to lose,just give it everything you can. Be ready to build-up and maximise your effort. Give half of your preparation time to mathematics. Start with basics. What kind of basics?Do you remember your primary school? what your teachers tell you or taught you. Addition,subtraction,multiplication and division. Yes, simple thing. BUT This time you will practise these 33 + 79= ? or 137 -49 = ? or 24 x 13=? or 960 % 24 = ? These kind of sums you should be able to compute within seconds.You will not qualify without these.How to do this kind of practise? There are many short tricks ,magic tricks available in the market.Don’t go for them.It will over burden you.You need some trick + a lot of practise.I will suggest an app Math Tricks - Android Apps on Google Play. Practise from here. At least for first 10 days.After that do it daily for 30 min max to max. It will be fun once you learn. start with Arithmetic portion that is average,speed ,time,number system percentage profit loss boats.All these chapters involve heavy calculations.Maths tricks will help you there . If possible ,join coaching classes where faculties are great .It is always helpful to learn from the experts. [recommended, if really weak in Mathematics] Be friends with people who are great at Maths.Fellow competitors also can help you. Then Practice and practice and practice. After that follow all the toppers startegy or whatever other guys suggested you. (This point must be done at the start of your preparation). Do not depend on your teachers to tell you which topics are more important. If you have chosen SSC as your career path then you should do your own research at the earliest. Search telegram study groups, facebook groups or the YouTube channels. be clever! Watch for the marks dynamics of the CGL /PO papers and prepare accordingly. For example, in SSC Geometry,Trigonometry is more important than Other chapters. So you should prepare those first because it will fetch you more marks.Its all cost-benefit ratio scenario. Best of Luck.