小明在操场周围种树，开始每隔3米种一棵，种到第9棵后，发现树苗不够了，于是决定重种，改为每隔4米种一棵，重种树时，有几棵树不必拔掉？
直接写出得数
1﹣0.375= 0.125×8= 280﹣45= 1.3÷0.25=
400÷600= 8.64×100=
+
=﹣
=
×
=
÷
= 12×
= 6÷
=
直接写出得数
0.5×400= 568﹣198=
÷
=
1÷
﹣÷1=
×12= 1.7+3.03=
13.5﹣5= 10﹣
﹣
=
24×0.5=
+
= 6﹣6÷6= 20×20%=
0.33= 7.2÷0.08= 4÷
= 12.5×6.4=
﹣
= 121×
=
直接写出得数
6÷
= 19÷
=
﹣
=
×
=
0.37+1.6= 4.8÷0.8= 1+8%= 2.5÷1.25=
0÷
=﹣
=
直接写出得数．
2306+400= 101﹣52=
×
=（0.25）2=
7.4﹣4=
×30%= 6÷17= 0.3+5=
1÷
= 41.64÷6.9≈ 0.24÷0.8=
÷2=