200﹣199+198﹣197+196﹣195+…+4﹣3+2﹣1= ×
+
×
+
×
+…+
×
=
1.8+62= 44÷= 2.4×5= 1÷
+
÷1=
= 3.4﹣1
= 2﹣1
=
+
+
+…+
=
8.8×(+
+
)= 0.75×16+
= 98÷
= 30
﹣(18.8+12×
)=