Find the unit digit of \(25^{45} \times 56^{78} \times 89^{12}\).
Answer: A
To find the unit digit of the product, we can find the unit digit of each factor.
The unit digit of \(25^{45}\) is 5, as any power of a number ending in 5 will end in 5.
The unit digit of \(56^{78}\) is 6, as any power of a number ending in 6 will end in 6.
The unit digit of the product will be the unit digit of \(5 \times 6 = 30\), which is 0. We don't even need to calculate the third term's unit digit, as any number multiplied by a number ending in 0 will also end in 0.