Shortcuts are big no-no when a child does his or her homework or writes a school exam. In many instances the student is asked to show how they arrived at a particular answer and are even awarded marks for following the proper steps to solve a sum. However, knowing these shortcuts can surely be beneficial and one of the advices we give to all our students is to learn shortcuts and use them when cross checking their answers as it saves valuable time.
So here are 3 addition tricks that will save you valuable time.
Addition of Similar digit numbers
One common question that we often see in question papers in some form or the other is the addition of similar digit numbers like 5+55, 7+77, 9+99+999 etc. Here is a quick way to solve these problems.
Let us take for example
The result of this particular problem 7+77+777 = 861
So what is the shortcut that you can use to solve this sum in your head?
- 7 is the common number in this sum so we take 7 and replace it with 1 so the sum now becomes 1+11+111.
- Now count the number of digits in each number i.e. 1=1 digit, 11= 2 digits, 111=3 digits and so on.
- Write down all the digits together in this case it would be 123.
- Now take the original common number 7 and multiply it by 123 = 861.
Addition of Consecutive numbers
Another common question that students tend to spend a lot of time and effort answering revolves around the addition of a consecutive series of numbers like 1 to 10, 6 to 13, 24 to 30 etc. Here is a quick way to solve these problems.
Let us take for example the series 44 to 78. Now actually taking a pen and paper and adding all these numbers would take some time even for the best of us but with the below method we can get to the same result with 3 easy and quick steps.
- First we will need to add the smallest number and the biggest number in this group, which in this case would be 44 and 78. 44 + 78 = 122
- We then multiply the result with total units in the series, which in this case is 34. 122 x 35 = 4270
- Finally we take the result of the product from the first two steps and divide it by 2. 42702 = 2135.
So the addition of the consecutive numbers from 44 to 78 is 2135.
Addition of all odd numbers starting from 1
This is another question that students always wish they knew a shortcut to solve. Well to tell you the truth there is a shortcut and a very simple one at that. All one needs to do is square the quantity of numbers in that particular series. web design company in rajahmundry web design company in kakinada web design company in vizag
Let us take for example the series 1 to 20. We know that between 1 and 20 there are 10 odd numbers and 10 even numbers so all we need to do is to find the square of 10. 10 x 10 = 100.
Let us take a few more examples to make sure of this simple method to answer what seems like a complicated question.
- Find the sum of the consecutive odd numbers in the series 1 to 88
- We know there are 44 odd numbers in this series i.e. 44 x 44 = 1936
- Find the sum of the consecutive odd numbers in the series 1 to 60
- We know there are 30 odd number in this series i.e. 30 x 30 = 900