一根长2米的圆柱形木头，截去2分米长的一段圆柱形小木块后，表面积减少了12.56平方分米，那么原来这根木头的体积是多少？
直接写得数．×=÷2=×= 68÷10%=×72%×÷=﹣+= 1﹣﹣= 80%﹣20%= 4×25%+16×25%=×÷×=（+）×12=
===== 0×1.27====== 1.5÷25%+1.5=
口算：× 45×÷10 0÷ 54×÷×64 12÷（﹣）×24 3×÷3×．
直接写出得数×= 1﹣=÷1=÷=×= 2.5×=×= 52×=×÷×= 0÷5×=
直接写得数．= 24÷====﹣==﹣×=
×
=
÷2=
= 68÷10%=
×72%
×
÷
=
﹣
+
= 1﹣
﹣
=
×
÷
×
=（
+
）×12=
=
=
=
=
= 0×1.27=
=
=
=
=
= 1.5÷25%+1.5=
×
45×
÷10 0÷
54×
÷
×64 12÷
（
﹣
）×24 3×
÷3×
×
= 1﹣
=
÷1=
÷
=
×
= 2.5×
=
×
= 52×
=
×
÷
×
= 0÷5×
=
= 24÷
=
=
=
=
﹣
=
=
=
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