Do you find mathematics boring and tedious? Do you find yourself making lots of mistakes while doing sums? If your teacher’s instructions fly over your head and you find it difficult to grasp the basic principles of mathematics, it is time to proceed to Plan B and learn some tips and tricks which will make this subject a fun and cool one.
First of all let us make division and multiplication easy for you. Can you tell if the number 5712 is divisible by 2, 3, 4, 5, 6, 9, etc., without even doing the actual sum?
No? Let’s understand the following tricks and see how easy and exciting mathematics really is.
Is it divisible by 2?
Take any number, no matter how big or small. If the digit in unit’s place is 0, 2, 4, 6 or 8, then the whole number is exactly divisible by 2. For example, let us take the number 5712. Since the last digit is 2, the number is divisible by 2. Can you tell if numbers 2184 and 8736 are also exactly divisible by 2?
Is it divisible by 3?
Add all the digits of the number. If the sum of digits is divisible by 3, then your number too is divisible by 3. Once again, let us take the number in first example, 5712. The sum of its digits (5+7+1+2) is 15 which is divisible by 3. Hence your number is also exactly divisible by 3. Can you tell if numbers 2184 and 8732 are also exactly divisible by 3?
Is it divisible by 4?
The trick to finding the answer to this one is similar to that of digit 2, but to know the answer you have to consider the last two digits of your number. In the example number 5712, the last two digits are 12 which appear in multiplication table of 4, so this number is also divisible by 4. Try out 2184 and 8736 and discover for yourself if this trick holds true.
Is it divisible by 5?
This is an easy one. For a number to be exactly divisible by 5, the last digit has to be either 0 or 5. So 5712 is not divisible by 5. Are 5710 or 25715 divisible by 5?
Is it divisible by 6?
If a number is divisible by both 2 and 3, then it is divisible by 6 as well. From earlier tips, we can find out that our number 5712 is divisible by both 2 and 3, so it is divisible by 6 as well. Now let us look at another number 102184. The last digit is 4, so it is divisible by 2. The sum of its digits (1+0+2+1+8+4) is 16, which is not divisible by 3. Hence the number is not divisible by 6. Try it for yourself.
Is it divisible by 8?
A number is divisible by 8 if the number formed by the last three individual digits is evenly divisible by 8. For example, the last three digits of the number 25840 is 840, which is evenly divisible by 8 so 25840 is also evenly divisible by 8.
Is it divisible by 9?
This tip is similar to divisible-by-3 rule. Add the digits. If the sum is divisible by 9, then the original number is divisible by 9 as well. However, it is not necessary for a number to be divisible by 9 even if it is divisible by 3. For example, the sum of digits in 32345712 is 27. Since 27 is divisible by 9, the original number is divisible by 9 as well. Let us look at another number 741417.
The sum of its digits (7+4+1+4+1+7) is 24. So 24 is divisible by 3 but not by 9, thus 741417 is not divisible by 9.
Is it divisible by 10?
Another easy one! If the last digit is 0, the number is divisible by 10. Out of numbers 32345710 and 32345715, can you tell which one is divisible by 10?
One of the main reasons that many of us struggle in math is because our basics and fundamentals are not fully developed or the mathematical concepts are not clear in our minds. Unlike many other subjects, math cannot be learned by cramming. You have to understand the basics and learning some tips and tricks will go a long way in helping you understand and make you enjoy this amazing subject.
And, of course, practice makes the man (or child) perfect!