用递等式计算．①÷[×（+）] ②1.05×（3.8﹣0.8）÷6.3 ③÷+÷④307×99+307 ⑤×43+56×75%+0.75 ⑥10﹣﹣4.25．
计算．﹣=﹣=+=+=﹣1=﹣=+=﹣= 1﹣=
计算．﹣（）+++（﹣）﹣﹣．
直接写得数：+=﹣=﹣=﹣= 1﹣=+=+=+=﹣= 2﹣=
直接写得数．+=﹣= 1﹣=+=+=+=
3﹣++ 5﹣+﹣1．
÷[
×（
+
）] ②1.05×（3.8﹣0.8）÷6.3 ③
÷
+
×43+56×75%+0.75 ⑥10﹣
﹣
=
﹣
=
+
=
+
=
﹣1=
﹣
=
+
=
﹣
= 1
﹣
﹣（
）
+
+
+（
﹣
）
﹣
．
+
=
﹣
=
﹣
=
﹣
= 1﹣
=
+
=
+
=
+
=
= 2﹣
+
=
﹣
= 1﹣
=
+
=
+
=
+
﹣
+
+
5﹣
+
﹣1．
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