一、口算。
$11 - 7 =$
$5 + 8 + 7 =$
$70 - 30 + 40 =$
$12 - 8 =$
$6 + 5 + 3 =$
$50 + 23 - 3 =$
$15 - 7 =$
$6 + 5 - 8 =$
$60 - 40 + 23 =$
$11 - 7 =$
$5 + 8 + 7 =$
$70 - 30 + 40 =$
$12 - 8 =$
$6 + 5 + 3 =$
$50 + 23 - 3 =$
$15 - 7 =$
$6 + 5 - 8 =$
$60 - 40 + 23 =$
答案
$11 - 7 = 4$
$5 + 8 + 7 = 13 + 7 = 20$
$70 - 30 + 40 = 40 + 40 = 80$
$12 - 8 = 4$
$6 + 5 + 3 = 11 + 3 = 14$
$50 + 23 - 3 = 73 - 3 = 70$
$15 - 7 = 8$
$6 + 5 - 8 = 11 - 8 = 3$
$60 - 40 + 23 = 20 + 23 = 43$
$5 + 8 + 7 = 13 + 7 = 20$
$70 - 30 + 40 = 40 + 40 = 80$
$12 - 8 = 4$
$6 + 5 + 3 = 11 + 3 = 14$
$50 + 23 - 3 = 73 - 3 = 70$
$15 - 7 = 8$
$6 + 5 - 8 = 11 - 8 = 3$
$60 - 40 + 23 = 20 + 23 = 43$
二、飞鸽送信。

答案
6+59=65
21+20=41
49+4=53
48+5=53
33+8=41
6+47=53
57+8=65
39+2=41
连线:
6+59、57+8 → 标有65的房子
21+20、33+8、39+2 → 标有41的房子
49+4、48+5、6+47 → 标有53的房子
21+20=41
49+4=53
48+5=53
33+8=41
6+47=53
57+8=65
39+2=41
连线:
6+59、57+8 → 标有65的房子
21+20、33+8、39+2 → 标有41的房子
49+4、48+5、6+47 → 标有53的房子
五、填一填。
$46 + 7 = □$

$58 + 9 = □$

$46 + 7 = □$
$58 + 9 = □$
答案
$46 + 7 = \boxed{53}$
$\boxed{40}$ 6
$\quad\quad\boxed{13}$
$58 + 9 = \boxed{67}$
$\boxed{50}$ $\boxed{8}$
$\quad\quad\quad\boxed{17}$
$\boxed{40}$ 6
$\quad\quad\boxed{13}$
$58 + 9 = \boxed{67}$
$\boxed{50}$ $\boxed{8}$
$\quad\quad\quad\boxed{17}$
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