有浓度为10%的盐水5kg，现在把它的浓度提高到20%，需要加盐还是加水？需要加多少千克呢？
直接写出得数 3×=÷= 18÷=××0=+=×=÷10= 1÷﹣÷1=
直接写得数．×=×3= 0÷=÷=×=×39=×=÷=÷=÷3=
直接写数对又快！==========
直接写出得数 10﹣0.1=+= 1÷= 14﹣﹣=×=﹣=×=（+）×72=
直接写出得数．×= 1÷0.9=÷0.8=×9÷×9= 5.6÷=×= 0÷=×=
=
÷
= 18÷
=
×
×0=
+
=
×
=
÷10= 1÷
﹣
×
=
×3= 0÷
=
÷
=
×
=
×39=
×
=
÷
=
÷
=
÷3=
=
=
=
=
=
=
=
=
=
=
+
= 1÷
= 14﹣
﹣
=
×
=
﹣
=
×
=（
+
）×72=
×
= 1÷0.9=
÷0.8=
×9÷
=
×
= 0÷
=
×
=
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