一、口算。
9 + 5 =
9 + 7 =
8 + 9 =
9 + 2 =
9 + 9 =
10 + 6 =
10 + 9 =
3 + 9 =
6 + 9 =
13 - 9 =
15 - 9 =
18 - 9 =
14 - 9 =
16 - 9 =
17 - 9 =

9 + 5 = 14
9 + 7 = 16
8 + 9 = 17
9 + 2 = 11
9 + 9 = 18
10 + 6 = 16
10 + 9 = 19
3 + 9 = 12
6 + 9 = 15
13 - 9 = 4
15 - 9 = 6
18 - 9 = 9
14 - 9 = 5
16 - 9 = 7
17 - 9 = 8

二、圈一圈，算一算。
1.

11 - 9 = $□$
2.
12 - 9 = $□$

1. （圈出9朵花）
$11 - 9 = 2$
2. （圈出9根小棒）
$12 - 9 = 3$

三、想一想，填一填。
1. 14 - 9 = $□$
先算：10 - 9 = $□$
再算：$□$ + $□$ = $□$
2. 17 - 9 = $□$
先算：10 - 9 = $□$
再算：$□$ + $□$ = $□$
3.

15 - 9 = $□$
$\begin{matrix}□ & □ \\+ & □\end{matrix}$
4.

18 - 9 = $□$
$\begin{matrix}□ & □ \\+ & □\end{matrix}$

1. $14 - 9 = \boxed{5}$
先算：$10 - 9 = \boxed{1}$
再算：$\boxed{4} + \boxed{1} = \boxed{5}$
2. $17 - 9 = \boxed{8}$
先算：$10 - 9 = \boxed{1}$
再算：$\boxed{7} + \boxed{1} = \boxed{8}$
3. $15 - 9 = \boxed{6}$
$\begin{matrix}\boxed{5} & \boxed{10} \\+ & \boxed{1}\end{matrix}$
4. $18 - 9 = \boxed{9}$
$\begin{matrix}\boxed{8} & \boxed{10} \\+ & \boxed{1}\end{matrix}$