口算 45+32= 500+300= 450+500= 50+800= 3000﹣1500=35÷7= 360﹣30= 730﹣700= 9×4= 3600﹣600=
直接写出得数．×= 1÷=÷60%=×15=﹣= 4.5+=×= 6.8÷10%=
3克盐放入40克水中，盐占水的几分之几？水占盐水的几分之几？
直接写得数 1÷=÷10=××=×=÷= 6×=
直接写出得数=== 3×===== 8×==
直接写得数： 1÷=+0.5=÷8=（+）×36=×= 5﹣=÷80%= 4﹣1﹣0.4=
×
= 1÷
=
÷60%=
﹣
×
= 6.8÷10%=
=
÷10=
×
×
=
×
=
÷
= 6×
=
=
=
= 3×
=
=
=
=
=
=
=
=
+0.5=
÷8=（
+
）×36=
×
= 5
﹣
=
÷80%= 4﹣1
﹣0.4=
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