How to Add 5 Consecutive Numbers Quickly

Step-by-Step Guide

1. 1

   Step 1: Mentally multiply the middle number by 5 ...

   finished!? That's all you do!. e.g. with your example 53 X 5 =
   265.
   
   Here's how to multiply this mentally:
   First separate 53 into 50 and
   3.
   
   Now 50 X 5 =
   250.
   
   Also 3 X 5 =
   15.
   
   Now add those separate answers. 250 + 15 =
   265.
2. 2

   Step 2: Learn how it works: Let the smallest number be (x - 2).

   Then the other 4 are (x
   - 1), (x), (x + 1) and (x + 2).
   
   The sum: (x
   - 2) + (x
   - 1) + (x) + (x + 1) + (x + 2) = 5x Using the above method: 10x/2 = 5x

Detailed Guide

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