12.5×32
=12.5*8*4
=100*4
=400
1.3-3.79+9.7-6.21
=1.3+9.7-3.79-6.21
=11-10
=1
十八分之十一÷[2-(四分之一+六分之五)]
=11/18*12/11
=12/18
=2/3