1. 直接写出得数。
$1.56 + 9.02 =$ $9.3×0.2 =$ $8.54 - 5.73 =$
$1.06×0.3 =$ $6.88 + 5.67 =$ $8.06×0.5 =$
$0.73×0.2 =$ $0.5×0.12 =$ $0.32×2 =$
$9×0.13 =$ $0.15 + 0.29 =$ $5.37 - 2.49 =$

$1.56 + 9.02 = 10.58$
$9.3×0.2 = 1.86$
$8.54 - 5.73 = 2.81$
$1.06×0.3 = 0.318$
$6.88 + 5.67 = 12.55$
$8.06×0.5 = 4.03$
$0.73×0.2 = 0.146$
$0.5×0.12 = 0.06$
$0.32×2 = 0.64$
$9×0.13 = 1.17$
$0.15 + 0.29 = 0.44$
$5.37 - 2.49 = 2.88$

2. 用简便方法表示下列各式。
$3.8×x =$ $a×5 =$ $m×n =$ $a×a =$
$a + a =$ $3.4×a×b =$ $4 + b + b =$ $4×b×b =$

$3.8×x = 3.8x$
$a×5 = 5a$
$m×n = mn$
$a×a = a²$
$a + a = 2a$
$3.4×a×b = 3.4ab$
$4 + b + b = 4+2b$
$4×b×b = 4b²$

3. 解方程。
$24x = 264$ $9×3 + x = 33.4$ $8x - 2.6 = 93.4$
$6÷6 + 4x = 57$ $3x - 2×7 = 40$ $4x + 13 = 365$

解：$24x = 264$
$x = 264÷24$
$x = 11$
解：$9×3 + x = 33.4$
$27 + x = 33.4$
$x = 33.4 - 27$
$x = 6.4$
解：$8x - 2.6 = 93.4$
$8x = 93.4 + 2.6$
$8x = 96$
$x = 96÷8$
$x = 12$
解：$6÷6 + 4x = 57$
$1 + 4x = 57$
$4x = 57 - 1$
$4x = 56$
$x = 56÷4$
$x = 14$
解：$3x - 2×7 = 40$
$3x - 14 = 40$
$3x = 40 + 14$
$3x = 54$
$x = 54÷3$
$x = 18$
解：$4x + 13 = 365$
$4x = 365 - 13$
$4x = 352$
$x = 352÷4$
$x = 88$

4. 看图列方程并解答。
(1)

(2)

(1)
解：3x + 25 = 166
3x = 166 - 25
3x = 141
x = 47
答：每个篮球47元。
(2)
解：3x - 60 = 180
3x = 180 + 60
3x = 240
x = 80
答：每份松树有80棵。