现有80粒重量、外形完全相同的珍珠和1粒外形相同、但重量较轻的假珍珠，怎样才能用一台天平尽快地将这粒假珍珠挑出来？
﹣=+= 1﹣=+= 1﹣=+=
填一填．
直接写得数．+=﹣= 0.2﹣=+=﹣=+2÷9= 2﹣﹣= 1.55﹣= 1﹣﹣+= 0.5﹣﹣=
计算．===== 1﹣===
看图计算下面各题．+= +=
﹣
=
+
= 1﹣
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+
= 1﹣
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+
+
=
﹣
= 0.2﹣
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+
=
﹣
=
+2÷9=
﹣
= 1.55﹣
+
=
=
=
=
=
= 1﹣
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=
=
+
=
+
=
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