Question

Solve each of the following Cryptarithm:

 A B
+3 7
 9 A

Answer 1

Two possibilities of A are:
\[(i)\text{ If }B + 7 \leq 9, A = 6\]
\[\text{ But clearly, if }A = 6, B + 7 \geq 9;\text{ it is impossible }\]
\[(ii)\text{ If }B + 7 \geq 9, A = 5\text{ and }B + 7 = 5 \]
\[\text{ Clearly, }B = 8\]
\[ \therefore A = 5, B = 8\]