DIVISIBILITY BY 11

Well, if you see a number how do you know if it is divisible by 11?
This is the trick.

• Find the sums of alternate digits
• Find the difference between the two sums
• If that difference can be divided by 11without a remainder, the original number is also divisible by 11

Example 1: Is 53812 divisible by 11?

Here let us find the sums of alternate digits.

• 5+8+2=15
• 3+1=4
• Difference=15-4=11
• 11 is divisible by 11. So 53812 is also divisible by 11.

Example 2:   Is 5480816 divisible by 11?

Let us find the sums of alternate digits

• 5+8+8+6=27
• 4+0+1=5
• Difference=27-5=22
• 22 is divisible by 11; so is 5480816  

Example 3:   Is  349875 divisible by 11?

Let us find the sums of alternate digits

• 3+9+7=19
• 4+8+5=17
• Difference=19-7=2
• 2 is not divisible by 11. So 349875 can not be divided by 11 without leaving a remainder.

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