一、口算。
30 ÷ 6 × 4 =
72 ÷ 9 × 6 =
(20 - 6) ÷ 2 =
48 ÷ 8 ÷ 2 =
84 + 6 - 50 =
(60 + 4) ÷ 8 =
35 - 5 - 20 =
25 - (7 - 2) =
7 × 8 - 20 =
50 - 8 + 2 =
3 × 6 ÷ 9 =
40 ÷ 5 + 17 =

30 ÷ 6 × 4 = 20
72 ÷ 9 × 6 = 48
(20 - 6) ÷ 2 = 7
48 ÷ 8 ÷ 2 = 3
84 + 6 - 50 = 40
(60 + 4) ÷ 8 = 8
35 - 5 - 20 = 10
25 - (7 - 2) = 20
7 × 8 - 20 = 36
50 - 8 + 2 = 44
3 × 6 ÷ 9 = 2
40 ÷ 5 + 17 = 25

二、计算下面各题。
$65 - 27 + 14$
$3 × 9 - 16$
$45 + 16 - 29$
$81 - (63 - 9)$
$84 - (19 + 16)$
$60 - 72 ÷ 9$
$7 × 8 - 30$
$54 ÷ 9 × 8$
$35 ÷ (11 - 4)$
$9 × (7 + 2)$
$70 - 26 - 16$
$68 - 28 ÷ 7$

$65 - 27 + 14$
$= 38 + 14$
$= 52$
$3 × 9 - 16$
$= 27 - 16$
$= 11$
$45 + 16 - 29$
$= 61 - 29$
$= 32$
$81 - (63 - 9)$
$= 81 - 54$
$= 27$
$84 - (19 + 16)$
$= 84 - 35$
$= 49$
$60 - 72 ÷ 9$
$= 60 - 8$
$= 52$
$7 × 8 - 30$
$= 56 - 30$
$= 26$
$54 ÷ 9 × 8$
$= 6 × 8$
$= 48$
$35 ÷ (11 - 4)$
$= 35 ÷ 7$
$= 5$
$9 × (7 + 2)$
$= 9 × 9$
$= 81$
$70 - 26 - 16$
$= 44 - 16$
$= 28$
$68 - 28 ÷ 7$
$= 68 - 4$
$= 64$

三、把下面每组算式合并成综合算式。
1. $26 + 35 = 61$
$61 - 8 = 53$

2. $31 - 21 = 10$
$10 ÷ 5 = 2$

1. $26+35-8=53$
2. $(31-21)÷5=2$