2 1.8 cm
3 、( 1)2(ab+ac+bc) (2)abc
4、6a？ Answer?
548 square decimeter
6.( 1)80 square meters (2) 2,400 cubic decimeters, or 2.4 cubic meters.
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1，( 1) 1.5m3 (2) 2.4kg。
2.( 1)64 cubic centimeters (2) can be cut into cubes like 12.