1. $60 + 20 + 5 =$ $80 - 30 + 4 =$
$65 + 20 =$ $84 - 30 =$
$5 + 3 + 70 =$ $9 - 4 + 50 =$
$75 + 3 =$ $59 - 4 =$
$65 + 20 =$ $84 - 30 =$
$5 + 3 + 70 =$ $9 - 4 + 50 =$
$75 + 3 =$ $59 - 4 =$
答案
1. $60 + 20 + 5$
$ = 80 + 5$
$ = 85$
$80 - 30 + 4$
$ = 50 + 4$
$ = 54$
$65 + 20 = 85$
$84 - 30 = 54$
$5 + 3 + 70$
$ = 8 + 70$
$ = 78$
$9 - 4 + 50$
$ = 5 + 50$
$ = 55$
$75 + 3 = 78$
$59 - 4 = 55$
答案依次为:85;54;85;54;78;55;78;55。
$ = 80 + 5$
$ = 85$
$80 - 30 + 4$
$ = 50 + 4$
$ = 54$
$65 + 20 = 85$
$84 - 30 = 54$
$5 + 3 + 70$
$ = 8 + 70$
$ = 78$
$9 - 4 + 50$
$ = 5 + 50$
$ = 55$
$75 + 3 = 78$
$59 - 4 = 55$
答案依次为:85;54;85;54;78;55;78;55。
2. 比一比,算一算。
$46 + 20 =$ $58 - 30 =$ $57 + 40 =$
$46 + 2 =$ $58 - 3 =$ $57 - 40 =$
$76 - 30 =$ $3 + 21 =$ $35 + 4 =$
$67 - 30 =$ $21 + 3 =$ $53 + 4 =$
$46 + 20 =$ $58 - 30 =$ $57 + 40 =$
$46 + 2 =$ $58 - 3 =$ $57 - 40 =$
$76 - 30 =$ $3 + 21 =$ $35 + 4 =$
$67 - 30 =$ $21 + 3 =$ $53 + 4 =$
答案
$46 + 20 = 66$
$58 - 30 = 28$
$57 + 40 = 97$
$46 + 2 = 48$
$58 - 3 = 55$
$57 - 40 = 17$
$76 - 30 = 46$
$3 + 21 = 24$
$35 + 4 = 39$
$67 - 30 = 37$
$21 + 3 = 24$
$53 + 4 = 57$
$58 - 30 = 28$
$57 + 40 = 97$
$46 + 2 = 48$
$58 - 3 = 55$
$57 - 40 = 17$
$76 - 30 = 46$
$3 + 21 = 24$
$35 + 4 = 39$
$67 - 30 = 37$
$21 + 3 = 24$
$53 + 4 = 57$
3. 把正确的得数圈出来。
$87 - 4(47$ $83)$ $76 - 50(71$ $26)$
$55 + 40(59$ $95)$ $63 + 2(65$ $83)$
$87 - 4(47$ $83)$ $76 - 50(71$ $26)$
$55 + 40(59$ $95)$ $63 + 2(65$ $83)$
答案
83 26 95 65
解析
87-4:先算7-4=3,再算80+3=83,圈83;76-50:先算70-50=20,再算20+6=26,圈26;55+40:先算50+40=90,再算90+5=95,圈95;63+2:先算3+2=5,再算60+5=65,圈65。
4. 直接写出得数。
$82 - 60 =$ $56 + 3 =$ $35 - 4 =$
$72 + 20 =$ $63 - 50 =$ $40 + 37 =$
$84 - 40 =$ $35 + 40 =$ $47 - 4 =$
$5 + 32 =$ $78 - 8 =$ $65 + 3 =$
$95 - 80 =$ $32 + 60 =$ $97 - 6 =$
$82 - 60 =$ $56 + 3 =$ $35 - 4 =$
$72 + 20 =$ $63 - 50 =$ $40 + 37 =$
$84 - 40 =$ $35 + 40 =$ $47 - 4 =$
$5 + 32 =$ $78 - 8 =$ $65 + 3 =$
$95 - 80 =$ $32 + 60 =$ $97 - 6 =$
答案
22;59;31
92;13;77
44;75;43
37;70;68
15;92;91
92;13;77
44;75;43
37;70;68
15;92;91
5. 找出得数是五十几的算式,在()里画“√”。
$78 - 20($$) ) $5 + 50() )
$10 + 46($$) ) $46 - 3() )
$33 + 20($$) ) $55 - 2() )

$78 - 20($$) ) $5 + 50() )
$10 + 46($$) ) $46 - 3() )
$33 + 20($$) ) $55 - 2() )
答案
√,√,√,×,√,√
解析
78-20=58(五十几,√);5+50=55(五十几,√);10+46=56(五十几,√);46-3=43(不是,×);33+20=53(五十几,√);55-2=53(五十几,√)
6. $27\xrightarrow{-2}□\xrightarrow{-10}□\xrightarrow{+40}□\xrightarrow{-3}□$
$□\xrightarrow{-3}□\xrightarrow{-40}□\xrightarrow{+20}□\xrightarrow{-30}26$
$□\xrightarrow{-3}□\xrightarrow{-40}□\xrightarrow{+20}□\xrightarrow{-30}26$
答案
25;15;55;52
79;76;36;56
79;76;36;56
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