c) 135135.137 - 135.137137 = 135.1001.137 - 135.137.1001 = 0
=> (1 + 3 + ... + 2015).(135135.137 - 135.137137) = (1 + 3 + ... + 2015). 0 = 0
d) 35.34 + 35.86 + 65.75 +65.45
= (35.34 + 35.86) + (65.75 + 65.45)
= 35.(34 + 86) + 65.(75 +45)
= 35. 120 + 65. 120
= (35 + 65).120
= 100.120 = 12000
e) 3.25.8 + 4.37.6 + 2.38.12
= 3.25.4.2 + 2.2.37.6 + 2.38.6.2
= 3.(25.4).2 + 2.2.6.(37 + 38)
= 3.100.2 + 4.6.75
= 600 + 6.(4.75)
= 600 + 6.300
= 600 + 1800
=2400
35*(34+86)+65*(75+45)
= 35*120+65*120
= 120*(35+65)
= 120*100
= 12000