# AB * CD = BA * DC

We know that the order of digits in a number matter, and we cannot randomly swap them around. Most of the time,

$\overline{AB} \times \overline{CD} \neq \overline{BA} \times \overline{DC} .$

How many ordered tuples of non-zero digits $$(A, B, C, D)$$ are there such that

$\overline{AB} \times \overline{CD} = \overline{BA} \times \overline{DC} ?$

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