Question

The last digit in the expansion of 8^1729 is... *

Answer 1

The last digit of 8^1729 is 8.

Given:

8^1729

To Find:

The last digit of  8^1729.

Solution:

The last digit of the following are,

8¹ = 8

8² = 4

8³ = 2

8⁴ = 6

8⁵ = 8 and it repeats the same

Therefore, the trend repeats in multiples of 4.

8¹⁷²⁹ = ((8⁴)⁴³²⁺¹)

        = (8⁴)⁴³²ₓ8¹    (i.e 8¹=8)

Hence, The last digit of 8^1729 is 8.

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