长+宽+高=4.8÷4=1.2米;
长=1.2×3÷(3+2+1)=0.6米;
宽=1.2×2÷(3+2+1)=0.4米;
高=1.2-0.6-0.4=0.2米;
体积=0.6×0.4×0.2=0.048立方米;
20/13-(4/5+7/13)
=(20-7)/13-4/5
=1-4/5
=1/5;
如果本题有什么不明白可以追问,
长+宽+高=4.8÷4=1.2米;
长=1.2×3÷(3+2+1)=0.6米;
宽=1.2×2÷(3+2+1)=0.4米;
高=1.2-0.6-0.4=0.2米;
体积=0.6×0.4×0.2=0.048立方米;
20/13-(4/5+7/13)
=(20-7)/13-4/5
=1-4/5
=1/5;
如果本题有什么不明白可以追问,