一、口算。
$52 - 7 =$
$28 + 40 =$
$63 - 4 =$
$4 + 29 =$
$38 - 9 =$
$69 + 3 =$
$80 - 40 =$
$35 + 34 =$
$49 - 27 =$
$58 + 4 =$
$23 + 60 =$
$25 - 9 =$
$12 + 36 =$
$96 - 42 =$
$66 - 20 =$
$16 - 8 =$
$41 + 37 =$
$78 - 26 =$
$56 - 40 =$
$46 - 23 =$
$6 + 88 - 60 =$
$25 + 7 + 12 =$
$66 - 8 + 30 =$
$60 - 4 - 26 =$
$33 + 62 - 44 =$
$92 - 60 + 8 =$
$32 + 5 - 17 =$
$74 - 12 + 8 =$
$23 + 9 - 22 =$
$77 - 60 + 9 =$

1.45
2.68
3.59
4.33
5.29
6.72
7.40
8.69
9.22
10.62
11.83
12.16
13.48
14.54
15.46
16.8
17.78
18.52
19.16
20.23
21.34
22.44
23.88
24.30
25.51
26.40
27.20
28.70
29.10
30.26

二、不计算，在得数较小的算式后面画“√”。
$\begin{cases} 26 + 21 \quad □ \\ 21 + 30 \quad □ \end{cases}$
$\begin{cases} 55 + 43 \quad □ \\ 55 + 40 \quad □ \end{cases}$
$\begin{cases} 48 - 9 \quad □ \\ 48 - 12 \quad □ \end{cases}$
$\begin{cases} 68 - 26 \quad □ \\ 78 - 26 \quad □ \end{cases}$

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