Tính bằng cách thuận tiện nhất:

a) 15 ´ 5 ´ 2 = ................................................... = ................................................... = ...................................................	b) 2 ´ 3 ´ 4 ´ 5 = ................................................... = ................................................... = ...................................................
c) 134 ´ 4 ´ 5 = ................................................... = ................................................... = ...................................................	d) 136 ´ 4 + 136 ´ 96 = ................................................... = ................................................... = ...................................................
e) 247 ´ 26 - 247 ´ 16 = ................................................... = ................................................... = ...................................................