IBPS RRB Office Assistant 2020 Prelim and Main – Strategy and last-minute tips for the Numerical Ability Section

This section of the RRB Office Assistant 2020 Prelim exam comprises of 40 Qs. The total time allotted for the Numerical AbilitySection and the Reasoning section is 45 minutes. There is no sectional time limit. One may allot 20-25 minutes of time for the Numerical Ability section.

The numerical ability section of the RRB Office Assistant 2020 Main exam comprises of 40 Qs, but the maximum marks are 50. One may allot around 25 to 30 minutes for this section though there is no sectional time limit.

There is a negative marking scheme for both Prelims and Mains exam, where 1/4th of the marks assigned for a question are deducted for each wrongly marked response. For Prelim and Main exams, there are minimum qualifying marks for individual tests. The marks obtained in the main exam only are considered for the final merit list.

The students should focus on the following question types for the Prelims exam.

  • Simplifications
  • Approximations
  • Number Series (Missing and Wrong Numbers)
  • Data Interpretation
  • Individual quant questions on Arithmetic

In addition to the above question types, the following subtopics are important for the Mains examination.

  • Quadratic Comparisons
  • Data Sufficiency (Important for Main exam; very rarely asked in Prelim exam)
  • Data Comparison (Important for Main exam)

Data Interpretation: Questions on Data Interpretation carry more weightage in the Main exam than in the Prelim exam. In the main exam, at least 15 questions are on Data Interpretation.

In the Prelim exam, questions on single graphs like Table, Bar Graph, Line Graph, Single Pie chart are asked whereas in the Main exam, question types include a combination of graphs like two pie charts, Caseletsetc. Five questions on caselet are asked in almost every year. In 2019, two caselets were given with five questions on each caselet. The questions based on Caselet should be attempted at the end.

Simplifications & Approximations:

Questions based on Simplifications and Approximations are asked quite frequently in the Prelims exam and carry 10 to 15 questions. In the mains exam, at the maximum fivesuch questions are asked. These questions are easy to solve and hence, students should not skip them.

To answer questions on Simplifications & Approximations and Data Interpretation, students should learn and practice the following:

  • Multiplication Tables (20X20)
  • Squares of first 25 Natural numbers
  • Cubes of first 20 Natural numbers
  • Powers of 2 (Up to 12)
  • Powers of 3 (Upto 7)
  • Fraction / Reciprocal values (Upto 12)
  • Complements of 100
  • Rules of Indices
  • Basic % concepts

Arithmetic Questions:

Questions here test knowledge of a student in fundamental concepts. These questions are important for both the Prelim and the Main examinations.

In Prelims exams, 5 to 15 questions are from arithmetic.

In mains exam, 10 to 15 questions are from arithmetic.

Important topics include – Ages, Percentages, Profit & Loss, Partnership, Time & Work, Boats & Streams, Trains, Mensuration, Simple & Compound Interest, Averages, Mixtures & Alligations, Permutations and Combinations, Probability etc.

Number Series and Quadratic Comparisons: Generally, there are five questions each on Number Series (Missing or Wrong No.). These are important for both the Prelim and the Main examinations. For mains exam questions on quadratic questions were asked in 2019. Questions on Quadratic comparisons are easy to attempt. Hence the student should certainly attempt these questions.

Data Sufficiency & Data Comparison:In the mains exam of 2017 and 2018, questions based on Data Sufficiency and in 2019, questions based on Data Comparison were asked in the Main exam. These questions demand a thorough understanding of the basics and are tricky to solve. These two question types at times can be asked in the Prelim exam as well, but their difficulty level would certainly be much lower, keeping in mind the basic nature of the exam.

The following table presents a topic-wise split of question types asked in the RRB Clerks 2017, 2018 & 2019 exams (Prelim & Main). [This is based on feedback given by T.I.M.E. students who have appeared for such exams earlier]

(Numerical Ability)
RRB Office Assistant Prelim 2019
(Comprising of all slots)
RRB Office Assistant Prelim 2018
(Comprising of all slots)
RRBOffice Assistant Prelim
(Comprising of all slots)
(Comprising of all slots)
Data Interpretation 10-15
(table + bar + caselet)
(Table, Caselet)
5 – 15
(Table, Bar, Caselet)
Number series 5 (Missing/Wrong) 5 (Missing/Wrong) 5 (Missing/Wrong) 5 (Missing/Wrong)
Arithmetic 5-10 10 15 5 -15
Quadratic equations 5 0 0 0-5
Speed Maths 10 15 (Approximations 5 and 10 simplifications) 15 (Approximations 5 and 10 simplifications) 10 – 15 (Approximations 5 and 10 simplifications)
Data Sufficiency 0 0 0 0
Data Comparison 0 0 0 0
Total 40 questions 40 questions 40 questions
  (Numerical Ability)
RRB Office Assistant Mains
RRB Office Assistant Mains
2018 (Multipurpose)
RRB Office AssistantMains
2017 (Multipurpose)
Data Interpretation 25
(Missing table, Bar graph, double Pie-chart, caselet)
(Missing table, Line graph, double Pie-chart, caselet)
  (Double Pie-Chart, Missing Table, Line graph)
15 – 25
  (Missing Table, Bar/line graph, Double Pie-Chart + Caselet)
Number series 0 0 0 0
Arithmetic 10 15 15 10 – 15
Quadratic equations 0 0 5 0 – 5
Speed Maths 0 0 0 0
Data Sufficiency 0 5 (2 statements) 5 (2 statements) 0 – 5 (statements)
Data Comparison 5 (2 quantities) 0 0 0
Total 40 questions 40 questions 40 questions

Strategy & Time-Management:

In order to maximise the score and to manage time effectively, we recommend the below mentioned plan for attempting questions.

It is advisable to attempt questions on - Simplifications & Approximations, Number Series, Quadratic Comparisons, Individual questions on Arithmetic, Data Comparisons and Data Sufficiency - first, before moving on to those on Data Interpretation.

Questions on Data Interpretation should be targeted at the end. Among these questions,Caselet-based questions should be attempted last.

Some useful Tips:

  • Going through the Analyses of previous years papers will help you understand what topics were asked in the exams, weightage of questions from each topic, pattern of questions etc.
  • Whether sectional time limit is specified or not, time management, speed, and accuracy play an important role in helping you clear your exams. Work on your speed and accuracy.
  • Practice questions daily. This will give you an edge over others, who are appearing for thee exams.
  • Tracking your performance on a regular basis helps you identify the areas / topics in which you are weak and need to boost up your preparation.
  • Answering the questions in a particular sequence, so as to maximise your attempts and your score, is very important. See the order given above.
  • Take ample online tests, topic wise as well as Mock Tests – these will help you understand your preparation levels and also assist you in time management, so that when you go for the actual exam, you give it a shot with confidence.

All the Best !!