Question

Find the digit at the ten's place of the number n = 7pow(281) × 3pow(264).

Answer 1

$= 7^{281} * 3^{264}$

$= 7^{4*70+1} * 3^{4*66}$

$= 7^{ 4^{70} }7 * 3^{ 4^{66} }$

$= 72401^{70 }7 * 81^{66 }$

any power of 1 will always result in 1 at unit placeand with multiplication of extra 7 the final value at the unit place will be 7

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