×= 1-= (7+)×8=
+= +6= 0.1+10%=
=
10001-999≈
20.97÷3.01≈
1+75%=
÷2=
0.2×50=
70%-20%=
4÷8×=
÷25%=
10×10%=
63÷90%=
5×÷5×=