2.64÷5÷2
=2.64÷(5x2)
=2.64÷10
=0.264
45.2x1.5—180.9÷3
=(45+0.2)x1.5—(180+0.9)÷3
=45x1.5+0.3—60-0.3
=4.5x15—4x15
=(4.5—4)x15
=0.5x15
=7.5
0.13x﹙3.6一1.8﹚+1.2x0.13
= 0.13x﹙3.6一1.8+1.2)
= 0.13x3
=0.39