从2100里“减去50，再加上20”，这称作一次操作，经过 次操作，所得的结果是0．
直接写出得数： 9.1﹣1.9= 7.2÷0.6= 0.25×8=+=×=÷=﹣= 52=．
直接写得数． 9﹣2.64= 56÷0.56=×12= 630×9%=÷= 1﹣=+= 0×÷=
直接写得数． 12.5+3.5= 87.05÷0.5=×= 18÷0.03=×=+= 2﹣= 13.2×0.5=×14=÷=
直接写得数． 1.4+1.5= 1﹣0.611= 1÷67= 1.6﹣13%= 12：16= 0÷35= 0.9+99×0.9=（56+14）×12=
直接写出得数．×80= 99÷= 9.6×=÷= 7÷=÷=×÷=×÷×=×0+=×÷=
+
=
×
=
÷
=
﹣
= 52=．
×12= 630×9%=
÷
= 1﹣
=
+
= 0×
÷
=
×
= 18÷0.03=
×
=
+
= 2﹣
= 13.2×0.5=
×14=
÷
=
×80= 99÷
= 9.6×
=
= 7÷
=
÷
=
×
÷
=
×
÷
=
×0+
=
×
÷
=
粤公网安备 44130202000953号