What is the digit in the unit’s place of 251?
Explanation:
Since 2 has a cyclicity of 4, i.e. 21 = 2, 22 = 4, 23 = 8, 24 = 16, 25 = 32, 26 = 64 ..., the last digits (2, 4, 8, 6) are in four cycles. ∴ On dividing 514, we get the remainder as 3.
∴ The last digits has tobe 23 = 8
Shortcut: Since cyclicity of the power of 2 is 4, so 251 can be written in 24(12) + 3 or unit digit will be 23 = 8.
Help us build a Free and Comprehensive Preparation portal for various competitive exams by providing us your valuable feedback about Apti4All and how it can be improved.