某小学三、四年级学生举行一周收废纸活动，三年级有35人，共收废纸420千克，四年级有45人，平均每人收集14千克，三、四年级一周共收废纸多少千克？
直接写出得数0.25×4= 0.82﹣0.56= 3.09+2.6= 6.03×100=1﹣= ﹣= += +=
口算．3.04﹣0.98= += 2÷9+= ×÷×=12×（+）= 6.3÷0.01= 1﹣58%=
直接写出得数．0.57+0.43= 4.13﹣1.3= 2.5×28=7.2÷0.6= 0.52= 3﹣1=（+）= 15÷×= ×8+8×=
快快算.6.0﹣2.4= 5.3+3.5= 4.7+3.6=20×13= 24×30= 640÷9== = =
口算下列各题．9.9+0.01= 0.08×0.5= 1.25×0.5×0.8== = ﹣+=
= 
﹣
= 
+
= 
+
=
+
= 2÷9+
= 
×
=
+
）= 6.3÷0.01= 1﹣58%=
=
+
）= 15÷
×
×8+8×
=
= 
= 
=
= 
= 
﹣
+
粤公网安备 44130202000953号