简便运算68+57+32

1个回答

  • 解题思路:(1)利用加法交换律简算;

    (2)(7)(11)(15)(16)利用乘法分配律简算;

    (3)(14)(18)利用减法的性质简算;

    (4)(5)把32拆成8×4利用乘法交换律与结合律简算;

    (6)(13)利用除法的性质简算;

    (8)(10)(17)(19)(20)利用加法交换律与结合律简算;

    (9)利用乘法交换律简算;

    (12)把44拆成4×11,利用乘法交换律与结合律简算.

    (1)68+57+32

    =68+32+57

    =100+57

    =157;

    (2)202×15

    =(200+2)×15

    =200×15+2×15

    =3030;

    (3)23.57-13.44-9.56

    =23.57-(13.44+9.56)

    =23.57-23

    =0.57;

    (4)32×125

    =4×(8×125)

    =4×1000

    =4000;

    (5)32×125×5

    =4×5×(8×125)

    =20000;

    (6)1120÷14÷8

    =1120÷(14×8)

    =1120÷112

    =10;

    (7)68×34-68×24

    =68×(34-24)

    =68×10

    =680;

    (8)36.6+25.8+36.6-25.8

    =36.6+36.6+(25.8-25.8)

    =73.2;

    (9)25×17×4

    =25×4×17

    =1700;

    (10)576+68+124+32

    =576+124+(32+68)

    =700+100

    =800;

    (11)82×43+18×43

    =(82+18)×43

    =100×43

    =4300;

    (12)25×44

    =25×4×11

    =1100;

    (13)72000÷25÷4

    =72000÷(25×4)

    =72000÷100

    =720;

    (14)326-168-132

    =326-(168+132)

    =326-300

    =26;

    (15)196×99+196

    =196×(99+1)

    =196×100

    =19600;

    (16)98×24-98×14

    =98×(24-14)

    =98×10

    =980;

    (17)2.95+23.47+5.05+6.53

    =(2.95+5.05)+(6.53+23.47)

    =8+30

    =38;

    (18)7.24-(3.68+1.24)

    =7.24-1.24-3.68

    =6-3.68

    =2.32;

    (19)25.38+19.52+34.62

    =25.38+34.62+19.52

    =60+19.52

    =79.52;

    (20)3.7+6.3+3.7-6.3

    =3.7+3.7+(6.3-6.3)

    =7.4.

    点评:

    本题考点: 运算定律与简便运算.

    考点点评: 简算注意抓住数字和运算符号的特点,选用适当的方法以及运算定律简算.