4.9+1.1= 7.5-5= 6-0.07= 1-0.81=
0.2+2.8= 8.4-4= 1.25+0.5= 5.1-0.8=
0.25+0.4= 0.37+0.3= 90×0.6= 0.4×500=
把棱长为5分米的正方体切成两个长方体,它的表面积增加了50平方分米.
1- =
2- =
4.7×0.35+0.47×4.2+0.047×23=