用递等式计算．250×3÷5 （260+124）÷8 884﹣160×5．
口算×6= += ×= ×6= ÷=÷= 1﹣= ﹣= ×4= ÷=
直接写得数．×= 0×= ÷=÷4= 12÷= 0.3×=×÷×= 0×+=
直接写出得数21×= ÷2= ×= ÷=÷= 12÷= 1÷= ×0=
直接写得数．20×= ÷= ×=÷6= ×12= ×=
直接写得数．×= ﹣= ×= ×=÷= ÷= ÷= ÷=
×6= 
+
= 
×
= 
×6= 
÷
=
÷
= 1﹣
= 
﹣
= 
×4= 
÷
=
×
= 0×
= 
÷
=
÷4= 12÷
= 0.3×
=
×
÷
×
= 0×
+
=
= 
÷2= 
×
= 
÷
=
÷
= 12÷
= 1÷
= 
×0=
= 
÷
= 
×
=
÷6= 
=
×
﹣
= 
×
= 
×
=
÷
= 
÷
= 
÷
= 
÷
=
粤公网安备 44130202000953号