罗老师要用1000元为学校买体育用品，他先花227.5元买了5个足球，并准备用剩下的钱买了一些蓝球，每个蓝球30.9元，罗老师还可以买多少个蓝球？你还能提出什么数学问题？
直接写得数．×=﹣=×=×=÷=÷=÷=÷=
直接写得数÷=×=﹣=×1.4= 12×= 24×=+= 0÷=
直接写得数== 3÷========
直接写得数．×16= 12÷= 0.3×=×÷=÷= 0×+=×÷×=
口算． 2×= 1.5÷=×0.8=×9= 1.2÷=÷2=÷= 2.4÷= 1÷5=÷3=
×
﹣
=
×
=
×
=
÷
=
÷
=
÷
=
÷
=
÷
=
×
=
﹣
=
×1.4=
= 24×
=
+
= 0÷
=
=
= 3÷
=
=
=
=
=
=
=
=
×16= 12÷
= 0.3×
=
×
÷
÷
= 0×
+
=
×
÷
×
= 1.5÷
=
×0.8=
×9= 1.2÷
=
÷2=
÷
= 2.4÷
= 1÷5
=
÷3=
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