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Solution

✅ Correct Option: 2

The unit's digit of powers of 2 follows a pattern. Looking at the first few powers:

21=22^1 = 2 → unit's digit is 22

22=42^2 = 4 → unit's digit is 44

23=82^3 = 8 → unit's digit is 88

24=162^4 = 16 → unit's digit is 66

25=322^5 = 32 → unit's digit is 22

26=642^6 = 64 → unit's digit is 44

27=1282^7 = 128 → unit's digit is 88

28=2562^8 = 256 → unit's digit is 66

The pattern of unit's digits repeats every 4 powers: 2,4,8,6,2,4,8,6,...2, 4, 8, 6, 2, 4, 8, 6, ...


To find where 220252^{2025} falls in this cycle, divide the exponent by 44:

2025÷4=5062025 \div 4 = 506 remainder 11


The remainder determines the unit's digit:

Remainder 11 → same unit's digit as 212^1 → 22

Remainder 22 → same unit's digit as 222^2 → 44

Remainder 33 → same unit's digit as 232^3 → 88

Remainder 00 → same unit's digit as 242^4 → 66


Since the remainder is 11, the unit's digit of 220252^{2025} is 22.

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