内容正文:
第二单元计算专项:带有小括号的混合运算
知识点梳理
1. 混合运算规则:算式里有小括号,要先算小括号里面的,再算小括号外面的。
2. 小括号的作用:改变运算顺序。
3. 分类运算要求:
① 小括号内只有加减法:先算括号里加减,再算括号外乘/除;
② 小括号内只有乘除法:先算括号里乘除,再算括号外加减;
③ 小括号内加减混合,括号外表内乘除;
④ 小括号内加减,括号外表内除法;
⑤ 连续带小括号(两个小括号同时计算)。
专项练习
考点1:括号内加法,括号外表内乘法
(1)(12+8)×3
(2)(15+5)×4
(3)(20+10)×2
(4)(7+9)×5
(5)(14+6)×6
(6)(11+9)×7
(7)(18+12)×1
(8)(13+7)×8
(9)(25+15)×2
(10)(16+4)×3
(11)(9+11)×9
(12)(22+8)×5
(13)(30+10)×2
(14)(17+13)×4
(15)(6+14)×7
(16)(21+9)×6
考点2:括号内减法,括号外表内乘法
(1)(20-8)×3
(2)(18-6)×4
(3)(25-10)×2
(4)(14-7)×5
(5)(30-12)×2
(6)(16-9)×6
(7)(22-10)×3
(8)(28-13)×4
(9)(15-5)×7
(10)(35-15)×2
(11)(19-11)×5
(12)(24-8)×3
(13)(32-12)×4
(14)(21-7)×6
(15)(26-14)×2
(16)(17-8)×8
考点3:括号内加法,括号外表内除法
(1)(10+14)÷4
(2)(13+11)÷6
(3)(5+7)÷3
(4)(15+9)÷8
(5)(20+16)÷9
(6)(12+12)÷4
(7)(7+17)÷6
(8)(18+18)÷9
(9)(4+14)÷3
(10)(16+20)÷4
(11)(11+13)÷8
(12)(10+26)÷9
(13)(19+17)÷6
(14)(8+16)÷4
(15)(14+22)÷9
(16)(12+24)÷6
考点4:括号内减法,括号外表内除法
(1)(14-6)÷2
(2)(15-9)÷3
(3)(20-8)÷4
(4)(18-10)÷2
(5)(24-15)÷3
(6)(30-12)÷6
(7)(22-14)÷4
(8)(17-8)÷1
(9)(25-16)÷3
(10)(28-19)÷3
(11)(32-14)÷2
(12)(21-12)÷9
(13)(26-8)÷2
(14)(36-18)÷6
(15)(19-11)÷4
(16)(27-18)÷9
考点5:括号内表内乘法,括号外加法
(1)(3×6)+15
(2)(4×5)+22
(3)(2×8)+14
(4)(7×3)+11
(5)(5×6)+24
(6)(8×2)+30
(7)(9×4)+16
(8)(6×6)+13
(9)(3×8)+21
(10)(5×5)+17
(11)(7×2)+25
(12)(4×7)+12
(13)(9×2)+28
(14)(6×3)+31
(15)(8×4)+10
(16)(5×7)+19
考点6:括号内表内乘法,括号外减法
(1)40-(3×6)
(2)35-(4×5)
(3)30-(2×8)
(4)29-(7×3)
(5)42-(5×6)
(6)50-(8×2)
(7)45-(9×4)
(8)41-(6×6)
(9)52-(3×8)
(10)40-(5×5)
(11)39-(7×2)
(12)44-(4×7)
(13)50-(9×2)
(14)49-(6×3)
(15)43-(8×4)
(16)54-(5×7)
考点7:括号内表内除法,括号外加法
(1)(12÷3)+18
(2)(16÷4)+25
(3)(18÷2)+13
(4)(24÷6)+20
(5)(21÷3)+15
(6)(36÷9)+30
(7)(32÷4)+11
(8)(45÷5)+14
(9)(28÷7)+22
(10)(10÷2)+27
(11)(42÷6)+16
(12)(54÷9)+19
(13)(14÷2)+24
(14)(40÷8)+31
(15)(30÷5)+17
(16)(63÷7)+12
考点8:括号内表内除法,括号外减法
(1)30-(12÷3)
(2)35-(16÷4)
(3)25-(18÷2)
(4)32-(24÷6)
(5)28-(21÷3)
(6)40-(36÷9)
(7)27-(32÷4)
(8)22-(45÷5)
(9)34-(28÷7)
(10)31-(10÷2)
(11)33-(42÷6)
(12)26-(54÷9)
(13)29-(14÷2)
(14)36-(40÷8)
(15)37-(30÷5)
(16)25-(63÷7)
考点9:双小括号(两个括号同时计算,再相乘)
(1)(3+5)×(10-7)
(2)(6+2)×(9-4)
(3)(4+4)×(8-3)
(4)(7+2)×(12-5)
(5)(5+3)×(11-6)
(6)(2+6)×(10-2)
(7)(8+1)×(13-7)
(8)(4+5)×(14-8)
(9)(3+6)×(9-3)
(10)(5+4)×(12-4)
(11)(7+1)×(11-5)
(12)(2+7)×(10-3)
(13)(6+3)×(15-8)
(14)(4+3)×(13-6)
(15)(5+2)×(14-7)
(16)(8+2)×(11-3)
考点10:双小括号(两个括号同时计算,再相除)
(1)(10+14)÷(5+3)
(2)(15+9)÷(7+1)
(3)(12+12)÷(8-4)
(4)(18+6)÷(9-5)
(5)(20+16)÷(4+5)
(6)(14+22)÷(10-4)
(7)(17+19)÷(2+4)
(8)(11+25)÷(7-3)
(9)(13+23)÷(9-5)
(10)(16+20)÷(3+6)
(11)(19+17)÷(8-2)
(12)(12+24)÷(5+1)
(13)(22+14)÷(10-4)
(14)(8+28)÷(4+2)
(15)(15+21)÷(9-3)
(16)(10+26)÷(7-3)
对应应用题
1. 商店有24个红皮球,12个黄皮球,每6个皮球装一盒,一共可以装几盒?
2. 一本书一共80页,已经看完32页,剩下的每天看8页,还要看几天?
3. 男生有18人,女生有14人,每4人一组做游戏,可以分成多少组?
4. 有50块糖果,拿走14块后,剩下的平均分给9个小朋友,每人分到几块?
5. 果园里苹果树25棵,梨树11棵,桃树的棵数是苹果树和梨树总和的2倍,桃树有多少棵?
6. 一根绳子长40米,剪掉16米,剩下的每3米做一根短绳,可以做几根短绳?
7. 小明带70元,买文具花掉25元,剩下的钱买5元一本的笔记本,可以买几本?
8. 一班有22人,二班有26人,平均分成8个小组打扫卫生,每组多少人?
9. 一共有45个橘子,吃掉9个,余下的每4个装一袋,可以装多少袋?
10. 养殖场有白兔17只,黑兔19只,把这些兔子每6只放进一个笼子,一共需要多少个笼子?
第 1 页 共 13 页
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参考答案
考点1:括号内加法,括号外表内乘法
(1)(12+8)×3 = 20×3 = 60
(2)(15+5)×4 = 20×4 = 80
(3)(20+10)×2 = 30×2 = 60
(4)(7+9)×5 = 16×5 = 80
(5)(14+6)×6 = 20×6 = 120
(6)(11+9)×7 = 20×7 = 140
(7)(18+12)×1 = 30×1 = 30
(8)(13+7)×8 = 20×8 = 160
(9)(25+15)×2 = 40×2 = 80
(10)(16+4)×3 = 20×3 = 60
(11)(9+11)×9 = 20×9 = 180
(12)(22+8)×5 = 30×5 = 150
(13)(30+10)×2 = 40×2 = 80
(14)(17+13)×4 = 30×4 = 120
(15)(6+14)×7 = 20×7 = 140
(16)(21+9)×6 = 30×6 = 180
考点2:括号内减法,括号外表内乘法
(1)(20-8)×3 = 12×3 = 36
(2)(18-6)×4 = 12×4 = 48
(3)(25-10)×2 = 15×2 = 30
(4)(14-7)×5 = 7×5 = 35
(5)(30-12)×2 = 18×2 = 36
(6)(16-9)×6 = 7×6 = 42
(7)(22-10)×3 = 12×3 = 36
(8)(28-13)×4 = 15×4 = 60
(9)(15-5)×7 = 10×7 = 70
(10)(35-15)×2 = 20×2 = 40
(11)(19-11)×5 = 8×5 = 40
(12)(24-8)×3 = 16×3 = 48
(13)(32-12)×4 = 20×4 = 80
(14)(21-7)×6 = 14×6 = 84
(15)(26-14)×2 = 12×2 = 24
(16)(17-8)×8 = 9×8 = 72
考点3:括号内加法,括号外表内除法
(1)(10+14)÷4 = 24÷4 = 6
(2)(13+11)÷6 = 24÷6 = 4
(3)(5+7)÷3 = 12÷3 = 4
(4)(15+9)÷8 = 24÷8 = 3
(5)(20+16)÷9 = 36÷9 = 4
(6)(12+12)÷4 = 24÷4 = 6
(7)(7+17)÷6 = 24÷6 = 4
(8)(18+18)÷9 = 36÷9 = 4
(9)(4+14)÷3 = 18÷3 = 6
(10)(16+20)÷4 = 36÷4 = 9
(11)(11+13)÷8 = 24÷8 = 3
(12)(10+26)÷9 = 36÷9 = 4
(13)(19+17)÷6 = 36÷6 = 6
(14)(8+16)÷4 = 24÷4 = 6
(15)(14+22)÷9 = 36÷9 = 4
(16)(12+24)÷6 = 36÷6 = 6
考点4:括号内减法,括号外表内除法
(1)(14-6)÷2 = 8÷2 = 4
(2)(15-9)÷3 = 6÷3 = 2
(3)(20-8)÷4 = 12÷4 = 3
(4)(18-10)÷2 = 8÷2 = 4
(5)(24-15)÷3 = 9÷3 = 3
(6)(30-12)÷6 = 18÷6 = 3
(7)(22-14)÷4 = 8÷4 = 2
(8)(17-8)÷1 = 9÷1 = 9
(9)(25-16)÷3 = 9÷3 = 3
(10)(28-19)÷3 = 9÷3 = 3
(11)(32-14)÷2 = 18÷2 = 9
(12)(21-12)÷9 = 9÷9 = 1
(13)(26-8)÷2 = 18÷2 = 9
(14)(36-18)÷6 = 18÷6 = 3
(15)(19-11)÷4 = 8÷4 = 2
(16)(27-18)÷9 = 9÷9 = 1
考点5:括号内表内乘法,括号外加法
(1)(3×6)+15 = 18+15 = 33
(2)(4×5)+22 = 20+22 = 42
(3)(2×8)+14 = 16+14 = 30
(4)(7×3)+11 = 21+11 = 32
(5)(5×6)+24 = 30+24 = 54
(6)(8×2)+30 = 16+30 = 46
(7)(9×4)+16 = 36+16 = 52
(8)(6×6)+13 = 36+13 = 49
(9)(3×8)+21 = 24+21 = 45
(10)(5×5)+17 = 25+17 = 42
(11)(7×2)+25 = 14+25 = 39
(12)(4×7)+12 = 28+12 = 40
(13)(9×2)+28 = 18+28 = 46
(14)(6×3)+31 = 18+31 = 49
(15)(8×4)+10 = 32+10 = 42
(16)(5×7)+19 = 35+19 = 54
考点6:括号内表内乘法,括号外减法
(1)40-(3×6)= 40-18 = 22
(2)35-(4×5)= 35-20 = 15
(3)30-(2×8)= 30-16 = 14
(4)29-(7×3)= 29-21 = 8
(5)42-(5×6)= 42-30 = 12
(6)50-(8×2)= 50-16 = 34
(7)45-(9×4)= 45-36 = 9
(8)41-(6×6)= 41-36 = 5
(9)52-(3×8)= 52-24 = 28
(10)40-(5×5)= 40-25 = 15
(11)39-(7×2)= 39-14 = 25
(12)44-(4×7)= 44-28 = 16
(13)50-(9×2)= 50-18 = 32
(14)49-(6×3)= 49-18 = 31
(15)43-(8×4)= 43-32 = 11
(16)54-(5×7)= 54-35 = 19
考点7:括号内表内除法,括号外加法
(1)(12÷3)+18 = 4+18 = 22
(2)(16÷4)+25 = 4+25 = 29
(3)(18÷2)+13 = 9+13 = 22
(4)(24÷6)+20 = 4+20 = 24
(5)(21÷3)+15 = 7+15 = 22
(6)(36÷9)+30 = 4+30 = 34
(7)(32÷4)+11 = 8+11 = 19
(8)(45÷5)+14 = 9+14 = 23
(9)(28÷7)+22 = 4+22 = 26
(10)(10÷2)+27 = 5+27 = 32
(11)(42÷6)+16 = 7+16 = 23
(12)(54÷9)+19 = 6+19 = 25
(13)(14÷2)+24 = 7+24 = 31
(14)(40÷8)+31 = 5+31 = 36
(15)(30÷5)+17 = 6+17 = 23
(16)(63÷7)+12 = 9+12 = 21
考点8:括号内表内除法,括号外减法
(1)30-(12÷3)= 30-4 = 26
(2)35-(16÷4)= 35-4 = 31
(3)25-(18÷2)= 25-9 = 16
(4)32-(24÷6)= 32-4 = 28
(5)28-(21÷3)= 28-7 = 21
(6)40-(36÷9)= 40-4 = 36
(7)27-(32÷4)= 27-8 = 19
(8)22-(45÷5)= 22-9 = 13
(9)34-(28÷7)= 34-4 = 30
(10)31-(10÷2)= 31-5 = 26
(11)33-(42÷6)= 33-7 = 26
(12)26-(54÷9)= 26-6 = 20
(13)29-(14÷2)= 29-7 = 22
(14)36-(40÷8)= 36-5 = 31
(15)37-(30÷5)= 37-6 = 31
(16)25-(63÷7)= 25-9 = 16
考点9:双小括号(两个括号同时计算,再相乘)
(1)(3+5)×(10-7)= 8×3 = 24
(2)(6+2)×(9-4)= 8×5 = 40
(3)(4+4)×(8-3)= 8×5 = 40
(4)(7+2)×(12-5)= 9×7 = 63
(5)(5+3)×(11-6)= 8×5 = 40
(6)(2+6)×(10-2)= 8×8 = 64
(7)(8+1)×(13-7)= 9×6 = 54
(8)(4+5)×(14-8)= 9×6 = 54
(9)(3+6)×(9-3)= 9×6 = 54
(10)(5+4)×(12-4)= 9×8 = 72
(11)(7+1)×(11-5)= 8×6 = 48
(12)(2+7)×(10-3)= 9×7 = 63
(13)(6+3)×(15-8)= 9×7 = 63
(14)(4+3)×(13-6)= 7×7 = 49
(15)(5+2)×(14-7)= 7×7 = 49
(16)(8+2)×(11-3)= 10×8 = 80
考点10:双小括号(两个括号同时计算,再相除)
(1)(10+14)÷(5+3)= 24÷8 = 3
(2)(15+9)÷(7+1)= 24÷8 = 3
(3)(12+12)÷(8-4)= 24÷4 = 6
(4)(18+6)÷(9-5)= 24÷4 = 6
(5)(20+16)÷(4+5)= 36÷9 = 4
(6)(14+22)÷(10-4)= 36÷6 = 6
(7)(17+19)÷(2+4)= 36÷6 = 6
(8)(11+25)÷(7-3)= 36÷4 = 9
(9)(13+23)÷(9-5)= 36÷4 = 9
(10)(16+20)÷(3+6)= 36÷9 = 4
(11)(19+17)÷(8-2)= 36÷6 = 6
(12)(12+24)÷(5+1)= 36÷6 = 6
(13)(22+14)÷(10-4)= 36÷6 = 6
(14)(8+28)÷(4+2)= 36÷6 = 6
(15)(15+21)÷(9-3)= 36÷6 = 6
(16)(10+26)÷(7-3)= 36÷4 = 9
应用题参考答案
1.(24+12)÷6 = 36÷6 = 6(盒) 答:一共可以装6盒。
2.(80-32)÷8 = 48÷8 = 6(天) 答:还要看6天。
3.(18+14)÷4 = 32÷4 = 8(组) 答:可以分成8组。
4.(50-14)÷9 = 36÷9 = 4(块) 答:每人分到4块。
5.(25+11)×2 = 36×2 = 72(棵) 答:桃树有72棵。
6.(40-16)÷3 = 24÷3 = 8(根) 答:可以做8根短绳。
7.(70-25)÷5 = 45÷5 = 9(本) 答:可以买9本。
8.(22+26)÷8 = 48÷8 = 6(人) 答:每组6人。
9.(45-9)÷4 = 36÷4 = 9(袋) 答:可以装9袋。
10.(17+19)÷6 = 36÷6 = 6(个) 答:一共需要6个笼子。
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