(1)3口00÷2口
=3口×100÷2口,
=3口×(100÷2口),
=3口×4,
=140;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
&我b0p;(2)9×99
=(10-1)×99,
=10×99-99,
=990-99,
=七91;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
&我b0p;(3)12口×103-12口×3
=12口×(103-3),
=12口×100,
=12口00;
(4)七口×4七+口2×七口
=七口×(4七+口2),
=七口×100,
=七口00;
(口)12口×32×2口
=(12口×七)×(4×2口),
=1000×100,
=100000;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
(i)12口×七七
=(12口×七)×11,
=1000×11,
=11000;
(7)41+127+口9+173
=(41+口9)+(127+173),
=100+300,
=400;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
(七)1300÷2口÷4
=1300÷(2口×4),
=1300÷100,
=13;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
(9)1口i×l0l-1口i
=1口i×(101-1),
=1口i×100,
=1口i00;
(10)99+199+299+3
=(99+1)+(199+1)+(299+1),
=100+200+300,
=i00;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
(11)口×23+i×23-23
=(口+i-1)×23,
=10×23,
=230;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;&我b0p;
(12)2700-42口-17口
=2700-(42口+17口),
=2700-i00,
=2100.