4 - IS Audit and Input Controls

E 40 35 5 5 check digit the technique uses an extra

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Unformatted text preview: ting digits 21 • Cross add the intervening digits ( 5 + 0 + 1 + 8 ) = 14 Total: 35 • Subtract from the next highest number ending in zero: 40 • Check digit (i.e., 40 - 35 = 5) 5 • Check digit: The technique uses an extra reference number added to an identification code bearing a mathematical relationship to the the other digits. – Examples: • Field: 4354545 • Check Digit: f(4354545) = 20 • New Field: 435454520 Field: 4354545 – When to use? Source: www.askdrmath.com/dr.math/problems/rsteven.7.3.96.html BUSI 335 Copyright © 2009-10 Y.M. Cheung, W. Tan, C. Woo and P. Bera 39 BUSI 335 Copyright © 2009-10 Y.M. Cheung, W. Tan, C. Woo and P. Bera 40 Record Level Record Level Record Level (cont…) Level (cont • Cross-field check sums: The technique su tec • Cross-field reasonableness check: reasonableness check: checks the value entered against the field whose value is the sum of other numeric fi fields. Check if the record should exist based on the value of a field. • Example: • Example: – Check if a specific transaction s...
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