This article is about how should one prepare for ISI entrance exam, along with how my journey was in that phase.

📘 My Journey to ISI Kolkata

Introduction

Hi, myself Aman Singh, currently pursuing B. Stat. Hons. at ISI Kolkata.
Here, I will explain the complete process of how I got admission to ISI Kolkata in detail for students aspiring to join ISI and for readers who would like to know.

Note: Just like Abhay Mahajan Sir (VOS) said, the following is not at all how you should prepare for any entrance exam. I don’t believe in luck, but you might consider it my luck that I got selected for such a premium institute with minimal effort compared to other students. That’s why I have added an Ideal Preparation (according to me) at the end.

Back-story

Background

I wasn’t aware of any Olympiads until I discovered that ISI does not conduct a written test for INMO qualifiers during my 12th grade. I was a good student, primarily interested in understanding the proofs, derivations, and explanations. That’s why my fundamentals were strong right from the start. In 10th grade (94% in boards), my favorite subject was physics (not math).

JEE & CUET

I studied JEE physics for 11th grade but only covered topics up to work, power, and energy. I got distracted during the COVID lockdown and struggled in my 11th grade. In mathematics, I only studied up to determinants (mainly for boards). In 12th grade, I started seriously but lost focus due to a flawed preparation strategy. I prioritized completing computer science for boards first, followed by class 11 chemistry (which I still don’t understand). Term 1 exams didn’t go well; I then became serious for Term 2.

Drop Year

I faced setbacks when I was admitted to the hospital due to severe typhoid, costing me exactly one month. Despite this, I prepared for the board exams and achieved a 94% score. Unprepared for JEE, I discovered ISI (though its application period had already ended). I decided to pursue a B. Tech or B.Sc. in statistics at DU, aligning with my interest in data science. I started preparing for CUET and secured admission to Ramanujan College for B.Sc. statistics at DU. However, I opted to take a drop for ISI in consideration of my emerging passion for data analysis, commencing my preparation in September. I invested in numerous books, printed study materials, and notes, and downloaded video lectures from YouTube (accessing the Wi-Fi of a friend’s friend).

Actual Preparation

Resources

I used YouTube lectures for JEE Advanced one-shot videos (Manzil 2.0 PW). After viewing each video, understanding, and solving all the questions in it, I watched chapter-wise previous year JEE questions (JEE Selection Express). I did not make any notes; instead, I took printouts of notes from a YouTube channel, Sid Academy. I watched the videos, read the notes, and updated them with anything new I learned.

Strategy

I maintained a register in which I noted down both questions and, if possible, all the ways to solve them—especially tricky, important, or those requiring revision of concepts. If I felt a chapter wasn’t strong enough, I watched other one-shot videos, usually by Vedantu’s Arvind Kalia or Unacademy’s NV Sir. This process should have been completed earlier, but I finished it by January. I started to revise all the important questions I wrote but stopped when I reached Calculus. I began writing my own self-made short notes, realizing many concepts were scattered and needed revision. This took me to mid-March.

Non-Routine Maths

Now I had to tackle number theory and geometry. I watched some PRMO lectures of VOS but didn’t fully grasp the concepts. So, I took the VOS ISI crash course, focusing only on the number theory and geometry lectures. I didn’t do any assignments or give mocks. I then made number theory and geometry short notes.

The Final Touch

Facing two options—TOMATO or PYQs—I decided to solve ISI CMI PYQs using the VOS ISI CMI course on YouTube and the channel Mathsmerizing. I took screenshots of good questions to revise later due to time constraints. That’s it. I didn’t solve any books, including TOMATO, Problem-Solving Strategies, Arihant JEE PYQs, Pearson Mathematics for JEE Advanced, ISI-CMI 10 Mocks UGA+UGB, etc.

Exam Day

I took JEE (solving only 14 questions in 3 hours of maths, with a math percentile of 98.89% and an overall percentile of 71%), then CMI (did not go well, not selected), followed by ISI (UGA: 18 correct, 3 wrong; UGB: 1 completely right, 1 almost right, 3 half solved, rest unattempted). I received an interview call, which I did not expect.

Results

For the interview, I had four PDFs of past-year interview questions, each with more than 80 questions, but I didn’t solve any. I revised maths from my notes and watched more YouTube videos. During the interview, the first question on combinatorics went well, and the second on geometry was solved with a hint, yet I made a silly mistake related to ratios. The third question on functional equations, which I had seen before, I couldn’t recall. I cracked the first part using hints, but they said the interview was over. Still, I got selected with a CRL of 107 and OBC rank of 9. Yes, I know the OBC quota saved me from my second drop.

More Stuff

Negligence

I wasted a lot of time on random things like shorts, YouTube, and Instagram. My daily schedule was too messed up; I slept around 12, woke up at 8:30, and only got to the study table around 12 pm daily. Due to my previous medical record, I had to go to the hospital for checkups every week, and I also had to go for ration every month, both of which took up my entire day. In the evenings, I sometimes went with my friends for recreation or just wasted time. Many days went poorly where I watched only 1-2 hours of lectures or solved 3-5 questions.

Optimism

Still, I didn’t give up or lose hope and tried my best until the end line. Even when reaching Kolkata, I was revising my notes on the train at the train station. My father and I didn’t sleep that night, and the next day, I gave the interview. My parents were supportive, but they didn’t realize what I was doing was good. They associated IIT, JEE, etc., with success, so they thought I was avoiding it and making weak life choices. However, when I got selected and told them about the institute, facilities, zero fees, average package, etc., they became happy (though not too much, as I would now have to leave them in Delhi to study at ISI Kolkata).

Ideal Preparation (according to me)

Note: I am explaining this from the perspective of a student with limited exposure to math, even at the JEE level.

Fundamentals 1

Complete the class 11th and 12th syllabus up to the JEE ADVANCED level using any reputable JEE book series such as Arihant, Cengage, A Das Gupta, Educative JEE, etc. or utilize online/offline coaching materials, video lectures, or classes. Ensure consistent revision of notes, regular practice of questions, and taking mocks for effective review. There’s no need to create comprehensive notes; instead, focus on jotting down essential terms, concepts, techniques, and approaches.

Fundamentals 2

Afterward, solve TOMATO objectives followed by subjective questions, seeking help from teachers, friends, telegram groups, or consulting solutions step by step. Additionally, study number theory and geometry through YouTube VOS lectures or PJ Sir lectures. While online courses are available, it’s advised to handle your preparation independently.

Necessity

Proceed to solve ISI/CMI previous year questions year-wise, preferably starting from recent years to older ones. Devote ample time to solve these independently or, at the very least, be able to recall the approach. Mark challenging questions throughout your preparation and regularly revise them, as they can significantly impact your selection. Optionally, use VOS and Mathsmerising channels for further practice and continue revising marked questions and short notes. If ISI-CMI mocks are available, solve them within the time limit.

Enthusiasm

For those with additional time or interest, consider IOQM PYQ -> PRMO/RMO PYQ -> INMO or any other Olympiad PYQ -> Olympiad books like Pearson, Excursion, Mathematical Circles, Pre College, Problem Solving Strategies, etc. -> Unit/topic-specific books for number theory, algebra, calculus, etc. and anything else as per individual preferences.

I hope you liked it. You would like to check my other articles on ISI Interview Guide and NOTES, Problems and other important resources to follow. Also before even trying to go to ISI and CMI like colleges, check out this article to know if it is even for you or not and what is my story behind saying this.