Method: ActiveMerchant::Billing::Check#checksum

Defined in:
lib/active_merchant/billing/check.rb

#checksum(digits) ⇒ Object

Routing numbers may be validated by calculating a checksum and dividing it by 10. The formula is:

(3(d1 + d4 + d7) + 7(d2 + d5 + d8) + 1(d3 + d6 + d9))mod 10 = 0

See en.wikipedia.org/wiki/Routing_transit_number#Internal_checksums



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# File 'lib/active_merchant/billing/check.rb', line 79

def checksum(digits)
  ((3 * (digits[0] + digits[3] + digits[6])) +
  (7 * (digits[1] + digits[4] + digits[7])) +
  (digits[2] + digits[5] + digits[8])) % 10
end