Question

1. Find the unit digit of expanded form
a) 100^14
b) 2912^12​

Answer 1

Answer:

use cyclicity

O cyclicity is always 0.

so 100^14 units digits is 0.

Cyclicity of 2 (for unit digit) is

2^1 = 2

2^2 = 4

2^3 = 8

2^4 = 6

2^5 = 2

it means repeat after 4

so 2912^12 have unit digit as 6.