Test divisibility rule “7” with example 111111111111.

“The difference between twice the unit digit of the given number and the remaining part of the given number should be a multiple of 7 or equal to 0.”
Step 1: Multiply the unit digit with 2
Step 2: Remove the unit digit of the number
Step 3: Find the difference of these two numbers
Step 4: If the anwer is divisible by 7, then the given number is also divisible by 7
Ex-> 665:-
5*2= 10
Removing 5 from 665, we get 66
66-10= 56 which is a multiple of 7
665 is divisible by 7.