(1) 71=7,72=49,73=34374=2401,75=16807 i.e. after index 4, the unit’s digit is repeated. ∴ On dividing 153 by 4, remainder = 1 ∴ Unit’s digit in the expansion of (2467)153=71=7 and unit’s digit in the expansion of (341)72=1 ∴ Required unit’s digit =7×1=7