In mathematics, divisibility rules are methods for quickly determining whether a given integer is divisible by a specific divisor without performing the division. One such rule is for determining divisibility by 37. A number is divisible by 37 if and only if the following condition holds:
Take the last two digits of the number and multiply the left-most digit by 3 and the right-most digit by 7. Subtract the smaller of the two products from the larger. If the result is divisible by 37, then the original number is divisible by 37.
