(1)1.29+3.7+0.71+6.3 =1.29+0.71+(6.3+3.7) =2+10 =12; (2)628×78+472×78 =(628+472)×78 =1000×78 =78000; (3)126×89×8 =126×8×89 =1000×89 =89000; (4)67×101-67 =67×(101-1) =67×100 =6700; (6)19×96-962÷74 =1824-13 =1811; (6)(620+480)÷60×4 =1000÷60×4 =20×4 =80; (7)400-(1300÷66+36) =400-(20+36) =400-66 =346; (8)86.7-(14.3-3.8&nbs5;) =86.7-10.6 =76.2. |