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Solution

Correct Option: 1

To find the unit's digit of 65006^{500}, examine the pattern in the unit's digits of powers of 6.

Calculate the first few powers of 6:

61=66^1 = 6 (unit's digit: 6)

62=366^2 = 36 (unit's digit: 6)

63=2166^3 = 216 (unit's digit: 6)

64=1,2966^4 = 1,296 (unit's digit: 6)


Every power of 6 ends in 6.

When any number ending in 6 is multiplied by 6, the result always ends in 6.

Example: 6×6=366 \times 6 = 36, then 36×6=21636 \times 6 = 216, then 216×6=1,296216 \times 6 = 1,296


Since every power of 6 has 6 in the unit's place, this holds for any exponent including 500.

Therefore, the unit's digit of 65006^{500} is 66.

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