10×5= 30×6= 700×7= 24﹣6= 64÷8=
87÷9= 28÷3= 6×4+6= 7×8+4= 4×3+2=
5×4+7= 7×2+9= 
+= 
﹣
= 1﹣
=
﹣= 198×6≈ 27×5≈ 52×4≈ 78×2≈
10×5= 30×6= 700×7= 24﹣6= 64÷8=
87÷9= 28÷3= 6×4+6= 7×8+4= 4×3+2=
5×4+7= 7×2+9= += ﹣= 1﹣=﹣= 198×6≈ 27×5≈ 52×4≈ 78×2≈
=
=
=
=
=
=
=
= 100×
=（
）×0=
米 ．
是72，这个数是多少？
÷
=
×
×4= 0.5﹣
=
= 1÷
=
+
=
×
=
÷8= 12×40%=
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