User:Prabhasclass8/sandbox/Prabhas Chandra Rai

Math tricks To square a number ending with 5  Let's take 85.Take the digit of the tens place ,i.e, 8 and multiply with its successor,i.e, 9.Result is 72.Place 25 at the end of the result.Now, the answer is 7225. To find the average of the numbers from 1 to 'n'  For example, we have to find the average of numbers from 1 to 19.Firstly, Add 1 and 19.The result is 20.Now divide the result by 2.The answer is 10.