长方体棱长的总和是96厘米,长:宽:高=3:2:1,它的表面积是 平方厘米,体积是 立方厘米.
= ÷ = (填小数)==.
= : =15÷ = %
= :20=4.5÷ = %=0.5 .
15÷ ==9: = %=0.75.
9: ==36÷ = :45= (填小数)