Step 1: Observe the transformation of each letter from "PAPER" to "OZODQ". Assign each letter a numerical value (A=1, B=2, ..., Z=26).
P(16) → O(15) : 16 - 1 = 15
A(1) → Z(26) : since 1 - 1 = 0, wrap around to 26
P(16) → O(15) : 16 - 1 = 15
E(5) → D(4) : 5 - 1 = 4
R(18) → Q(17) : 18 - 1 = 17
Step 2: Notice the pattern — each letter is shifted back by 1 alphabetically, with wrap-around from A to Z.
Step 3: Apply this same rule to the word "BOARD":
B(2) → A(1)
O(15) → N(14)
A(1) → Z(26) (wrap around)
R(18) → Q(17)
D(4) → C(3)
Step 4: Therefore, "BOARD" is coded as "ANZQC".