一串珠子按下面的顺序排列，第30颗是什么颜色？第50颗呢？
口算题．×=×=×9=××0=+=×11= 5﹣﹣=×9×7=
口算×15=×2=×=×=×= 1×=×=×34=×=×=×=×=×=×=×=×24=×=×30= 28×=×=
直接写出得数×15=×2=×=×= 1×=×=×34=×=×=×=×=×=
计算． 1×4.8 2×3.5 2.3×1 2×0.63．
口算：×15=×2=×=×=×= 1×=×=×34=×=×=×=×=
×
=
×
=
×9=
×
×0=
+
=
×11= 5﹣
﹣
=
×9×7=
×15=
×2=
×
=
×
=
×
=
=
×
=
×34=
×
=
×
=
×
=
×
=
×
=
×
=
×
=
×24=
×
=
×30= 28×
=
×
=
×15=
×2=
×
=
×
=
=
×
=
×34=
×
=
×
=
×
=
×
=
×
=
×4.8 2
×3.5 2.3×1
2
×0.63．
×15=
×2=
×
=
×
=
×
= 1×
=
×
=
×34=
×
=
×
=
×
=
×
=
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