When i was studying in the junior classes, I was taught about the divisibility rules for 2, 3, 4, 5, 6, 8, 9, 10 etc... I asked my teacher that may be by mistake you have skipped the rule for number 7. He told that there is no divisibility rule for 7. I was surprised, but no solution at that time.
Well, after many years... I came across rule for not only 7, but for given any prime number using vedic mathematics... it sounds good!
I am sharing that with all the readers.
This is very interesting. I had been trying to find a rule for seven also. Before I stumbled across this rule you have here, all I would do is put the closest divisible in my head to that number and subtract it from the number in question, then if that answer was for example 105, then I would know that number was a divisible of seven. I'm glad to see someone come up with a defined rule that works. Good job.
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