Unit’s digit of any number that can be expressed as a power of any natural number between 1 and 9:- 

(i) The units’ digit of any number expressed as a power of 2 is any of the digits 2, 4, 8, 6 as 2¹ = 2, 2² = 4, 2³ = 8, 2⁴ = 16, 2⁵ = 32, ....... etc.

(ii) The units' digit of any number expressed as a power of 3 is any of the digits 3, 9, 7, 1 as 3¹= 3, 3²= 9,3³ = 27, 3⁴ = 81, 3⁵ = 243, ....... etc.

(iii) The units’ digit of any number expressed as a power of 4 is 4 if the power is odd and 6 if the power is even as 4¹ = 4, 4² = 16, 4³ = 64, 4⁴ = 256, ......etc.

(iv) The units' digit of any number expressed as a power of 5 is always 5 as 5¹ = 5, 5² = 25, 5³ = 125, ........ etc

(v) The units' digit of any number expressed as a power of 6 is always 6 as 6¹ = 6, 6² = 36, 6³ = 216, ........ etc.

(vi) The units' digit of any number expressed as a power of 7 is any of the digits 7, 9, 3, 1 as 7¹ = 7, 7² = 49, 7³ = 343, 7⁴ = 2401, ........ etc

(vii)The units' digit of any number expressed as a power of 8 is any of the digits 8, 4, 2, 6 as 8¹ = 8, 8² = 64, 8³ = 512, 8⁴ = 4096, ........ etc.

(viii) The units' digit of any number expressed as a power of 9 is 9 if the power is odd and 1 if the power is even as 9¹ = 9, 9² = 81, 9³ = 729, 9⁴ = 6561, ........ etc.