Tricks on getting the sum of consecutive numbers inclusive of two numbers.

1. Choose any two counting numbers (or signed numbers)
2. Add the numbers
3. Subtract the smaller number from the larger. Then add one (1) to the difference.
4. Multiply half the sum(in step 2) by the result in step 3.
   OR: Multiply half the result in step 3 by the sum (in step 2).

Example:

Find the sum of all the numbers from 5 to 26.


Step 1: 5 & 26

Step 2: 5 + 26 = 31

Step 3: 26 - 5 = 21
           21 + 1 = 22

Step 4: Multiply half of 22 by 31 :

            11 x 31 = 341

     OR: Multiply half of 31 by 22:

            15.5 X 22 = 341


Therefore, the sum of all the numbers from 5 to 26 is 341.