## >> Monday, June 29, 2009

Introduction:
This article will demonstrate how to verify if a numbver is divisible by 7 or not. It will demonstrate using simple vedic ways so that any student, teacher or maths lover can learn it easily.

Testing technique:
1. Double the last digit of the number.
2. Subtract it from the remaining number.
3. Then test the remainder if divisible by 7.
4. If remainder is a large number, repeat steps 1 to 3 again and again till you get a simple number that you can test mentally.

Example:
Let's test 791 to find if it is divisible by 7 or not.
step 1: Lat digit is 1 X 2 = 2
step 2: Remaining number 79 - 2 = 77
step 3: We can say easily that 77 is divisible by 7
Hence, 791 is dividible by 7

Let's test a bit complex number:
7856492

Step 1: 2 X 2 =4
Step 2: 785649 - 4 = 785645 (this is a big number. Repeat step 1 and 2 now)
Step 3: 5 X 2 = 10
Step 4: 78564 - 10 = 78554
Step 5: 4 X 2 = 8
Step 6: 7855 - 8 = 7847
Step 7: 7 X 2 = 14
Step 8: 784 - 14 = 770

Now, easily we can say that 770 is divisible by 7.
Hence the whole complex number 7856492 is divisible by 7.

Hope this helps.

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