一、口算。（每题1分，共30分）
$4.8 - 4.08 =$ $56\times0.02 =$ $23.4 + 3.5 + 26.6 =$
$10\div100 =$ $1.3 + 2.95 =$ $3.56\times(0.25 + 0.75) =$
$9.99\div0.9 =$ $2.5\times0.5 =$ $8.5 - 4.2 - 3.8 =$
$320 - 50 =$ $90\div60 =$ $6.4\div(3.6 - 0.4) =$
$27\div90 =$ $0.64 - 0.46 =$ $30\times2.5 + 70\times2.5 =$
$1.3\times0.06 =$ $96\div0.3 =$ $770\div1.25\div0.8 =$
$40.8\div4 =$ $0.03 + 0.87 =$ $1.3\times7.8 - 0.3\times7.8 =$
$5.1 - 4.3 =$ $400\times0.04 =$ $99\times2.9 + 2.9 =$
$2.58\times0.3 =$ $8.1\div2.7 =$ $3.55\div4\div3.55 =$
$302 + 198 =$ $50\times24 =$ $72.8 + 7.28 + 28.2 =$

0.72 1.12 53.5
0.1 4.25 3.56
11.1 1.25 0.5
270 1.5 2
0.3 0.18 250
0.078 320 770
10.2 0.9 7.8
0.8 16 290
0.774 3 0.25
500 1200 108.28

二、解方程。（每题3分，共27分）
$5x + 6.32 = 8.72$ $6.4x - 3.2x = 2.56$ $0.7(x + 0.48) = 0.49$
$2.6x + 0.5 = 1.124$ $0.5x - 6.4 - 2.6 = 3.2$ $23\times0.2 + 1.7x = 8$
$7x\div3 = 8.19$ $2.2x - 0.5\times2 = 10$ $x - 12.5 + 8.5 = 11$

$x = 0.48$
$x = 0.8$
$x = 0.22$
$x = 0.24$
$x = 24.4$
$x = 2$
$x = 3.51$
$x = 5$
$x = 15$