Number System questions are quite common, not only for IBPS RRB but also for other banking exams. IBPS RRB number system questions are easy to solve and hence, considered to be scoring. However, the thing with number system questions is that you need to know certain tricks to solve the questions. Otherwise, solving the questions becomes next to impossible. After all, could you really find the sum of the first 250 odd numbers in seconds? This is the reason why you need to learn the tricks. Here, we are going to take a look at some of the number systems questions that are common in RRB exam and some of the tricks that you can use to solve them effectively.
Common Types for IBPS RRB Number System Questions
Number system questions encompass a variety of different questions. Some of the questions are rare, whereas others are more common. Similarly, some questions are more difficult than the rest. Let us take a look at some of the common questions and see how frequently they come in the exam.
|Sum of Numbers||Easy to Moderate||Common|
|Properties of Numbers||Easy||Common|
These are just some of the types of questions that are included in number systems. The given types of questions have found to be frequent in the past few years question papers. The trend is expected to continue for IBPS RRB 2018 as well. So, it would be better if you include these subtopics in your bank exam preparation.
Tricks to Solve IBPS RRB Number System Questions
Let us take a quick look at some of the tricks that you can use to solve the types of questions mentioned above.
Tricks for Divisibility
As seen from the charts above, divisibility questions are rare. However, you never know when they might come in the exam! On top of that, there is always the possibility that you can use the tricks for divisibility to get the solutions to other questions. Let us take a look at some of the rules of divisibility which would help you to find whether a particular number is divisible by another number or not –
For numbers divisible by 3
A number is said to be divisible by 3 if the sum of the digits of the number is also divisible by 3. For example, 342321 is divisible by 3 as 3+4+2+3+2+1=15, which is also divisible by 3.
For numbers divisible by 4
A number is said to be divisible by 4 if the last two digits are 00. The number would also be divisible by 7 if the last two digits are divisible by 4. For example, 12983400 is divisible by zero. Similarly, 3390127620 is also divisible by 4 as the number formed by the last two digits ’20’ is divisible by 4.
For numbers divisible by 5
This one is simple! A number is divisible by 5 if the last digit is either ‘0’ or ‘5’. For example, 45921870 and 33291765 both are divisible by 5.
For numbers divisible by 6
A number is divisible by 6 if it is divisible by 3 and 2 both. For example, suppose you are given the number 23862. Since the last digit is 2, it is divisible by 2. Now when we add the digits, we get 21, which is also divisible by 3. So, the number 23862 is divisible by 6.
For numbers divisible by 7
A number would be divisible by 7 if the number in the difference between double of the digit in units place and the remaining number is divisible by 7. For example, let us say that the number is 343. The double of the digit in the unit’s place is 3×2=6. The remaining numbers are 34. Now, the difference between 34 and 6 is 28. Since 28 is divisible by 7, the number 343 is also divisible by 7.
For numbers divisible by 8
A number is divisible by 8 if the last three digits are 000 or the last three digits are divisible by 8. For example, 534864 is divisible by 8 as the last three digits ‘864’ is also divisible by 8.
For numbers divisible by 9
The divisibility rule for number 9 is similar to that of 3. If the sum of all the digits of the number is divisible by 9, then the number is also divisible by 9.
For numbers divisible by 10
If the last digit of the number is 0, then the number is divisible by 10.
Tricks for Sum of Numbers
In such type of questions, you would be asked to find the sum of numbers within a given range. For example, you may be asked to find the sum of the first 20 natural numbers. So, how can you solve questions like that? Let’s find out.
For finding the sum of the natural numbers from 1 to n
for example, the sum of numbers from 1 to 50 =50 (50+1)/2=1275
For finding the sum of squares of the first n natural numbers
For finding the sum of cubes of the first n natural numbers
So, these were some of the formulas and tricks that you can use to solve IBPS RRB number system questions. Hope this article was of help to you. For more such useful articles, keep browsing our website. At Topprnotes, we help you study smart.
All the best!