一、口算。
$5.5+0.25=$ $6.5-4.7=$ $9.9÷0.9=$
$12.5×8=$ $0.84÷4.2=$ $0.17×0.4=$
$4.8÷0.16=$ $0.45+0.6=$ $1.5×0.3=$
$2-0.01=$ $0.48÷0.8=$ $0.07×0.3=$
$0.64÷0.4=$ $0.85×0.4=$ $0.184+0.116=$
$2.6+3.8=$ $0.64-0.36=$ $3.5÷7=$
$\frac {3}{5}+\frac {1}{6}=$ $\frac {4}{7}+\frac {4}{7}=$ $\frac {1}{5}-\frac {1}{8}=$
$\frac {3}{4}-\frac {3}{10}=$ $\frac {11}{15}-\frac {3}{5}=$ $\frac {5}{4}+\frac {3}{14}=$

 $5.5+0.25=5.75$
$6.5-4.7=1.8$
$9.9÷0.9=11$
$12.5×8=100$
$0.84÷4.2=0.2$
$0.17×0.4=0.068$
$4.8÷0.16=30$
$0.45+0.6=1.05$
$1.5×0.3=0.45$
$2-0.01=1.99$
$0.48÷0.8=0.6$
$0.07×0.3=0.021$
$0.64÷0.4=1.6$
$0.85×0.4=0.34$
$0.184+0.116=0.3$
$2.6+3.8=6.4$
$0.64-0.36=0.28$
$3.5÷7=0.5$
$\frac{3}{5}+\frac{1}{6}=\frac{23}{30}$
$\frac{4}{7}+\frac{4}{7}=\frac{8}{7}$
$\frac{1}{5}-\frac{1}{8}=\frac{3}{40}$
$\frac{3}{4}-\frac{3}{10}=\frac{9}{20}$
$\frac{11}{15}-\frac{3}{5}=\frac{2}{15}$
$\frac{5}{4}+\frac{3}{14}=\frac{41}{28}$

 

二、计算下面各图形的表面积和体积。

表面积：(3×4.5+3×6+4.5×6)×2=117(cm²)
体积：3×4.5×6=81(cm³)
表面积：4×4×6=96(cm²)
体积：4×4×4-2×2×2=56(cm³)