考點:整數(shù)四則混合運算,運算定律與簡便運算
專題:運算順序及法則,運算定律及簡算
分析:274+87-74-87利用加法交換律與結合律簡算;
397×101-397,(67×76+76×58)×8,(125×99+125)×64,利用乘法分配律簡算;
其它利用除法的性質簡算和除法法則計算.
解答:
解:274+87-74-87
=274-74+(87-87)
=200;
3600÷48
=3600÷12÷4
=300÷4
=75;
397×101-397
=397×(101-1)
=397×100
=39700;
6500÷(65×25)
=6500÷65÷25
=100÷25
=4;
(67×76+76×58)×8
=76×(67+58)×8
=76×(125×8)
=76×1000
=76000;
(125×99+125)×64
=125×(99+1)×64
=125×100×8×8
=12500×8×8
=100000×8
=800000;
1200÷25
=1200÷5÷5
=240÷5
=48;
375÷25
=375÷5÷5
=75÷5
=15;
260÷5=52;
3500÷125
=3500÷1000×8
=3.5×8
=28;
7250÷125
=7250÷1000×8
=7.25×8
=58;
22400÷56
=224÷56×100
=4×100
=400;
125×11×8×7
=125×8×(11×7)
=1000×77
=77000;
88×25
=11×(8×25)
=11×200
=2200;
2200÷25
=100÷25×22
=4×22
=88;
33000÷125
=1000÷125×33
=8×33
=264;
7800÷25÷4
=7800÷(25×4)
=7800÷100
=78;
18000÷8÷125
=18000÷(8×125)
=18000÷1000
=18;
1800÷(18×25)
=1800÷18÷25
=100÷25
=4;
690÷(23×5)
=690÷23÷5
=30÷5
=6;
2700÷54
=2700÷9÷6
=300÷6
=50;
4500÷18
=4500÷9÷2
=500÷2
=250.
點評:整數(shù)混合運算的掛件是抓住運算順序,適當運用合理的方法和運算定律簡算.