How to know if a number is divisible by 7?
Let us explore the divisibility rule of 7.
Answer: The rule is that the last digit of the given number should be multiplied by 2 and then subtracted with the rest of the number leaving the last digit. If the difference is 0 or a multiple of 7, then it is divisible by 7.
Let us understand the rule in detail:
Follow the loop:
- Separate the last digit from the number.
- Double the last digit.
- Subtract that from the truncated number thus obtained.
- Continue this process till you are left with only one digit.
- If the single digit at the end is 0 or 7, then the original number is divisible by 7.
For example: 945
94 - 2(5) = 94 - 10 = 84
8 - 2(4) = 8 - 8 = 0
So, 945 is divisible by 7.
Hence, the divisibility rule of 7 is to double the last digit and subtract from the remaining number and continue this until only one digit remains. If the end result is 0 or 7, then the original number is divisible by 7.
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