Let N be your UCR card number, which is made up of six figures:

N=X₅X₄X₃X₂X₁X₀ we have the hexadecimal numbers (without sign) n₁=$X₅X₄X₃ and n₀=X₂X₁X_0, for example, for the card N=C29876 you have to n₁=$C29 and n₀=$876. From these numbers do the following (not 1 = $29 0 = $876 rebase unless noted):

A. Represent n₁ and n₀ as positive numbers

B. Compute n₁-n₀ using base's complement.

C. If the value obtained in b. is valid, convert it to a decimal base, otherwise justify why it is invalid.