(1)18.3-6.25-3.75+12.7
=(18.3+12.7)-(6.25+3.75)
=31-10
=21;
(2)195÷125×25
=195÷(125÷25)
=195÷5
=39;
(3)125×(24+8)×25
=(125×8)×(4×25)
=1000×100
=100000;
(4)1.78+3.76+8.22+6.24
=(1.78+8.22)+(3.76+6.24)
=10+10
=20;
(5)264+36×50-7236÷18
=264+1800-402
=2064-402
=1662;
(6)55×[(154-64)÷18]
=55×[90÷18]
=55×5
=275.