Concept Used: after multiplication by 3, the value of unit digit repeats after a periodicity of 4 , as it can be seen below 31 = 3 32 = 9 33 = 7 34 = 1 35 = 3 Calculation: (2153)167 = ((2153)4)41×(2153)3 Unit digit of the multiplication of (2153)167 = 1 × 7 = 7 ∴ required unit digit = 7