考點(diǎn):整數(shù)四則混合運(yùn)算,運(yùn)算定律與簡便運(yùn)算
專題:運(yùn)算順序及法則,運(yùn)算定律及簡算
分析:25×32×125、48×20×125利用乘法交換律與結(jié)合律簡算;
739×98+739、87×102利用乘法分配律簡算;
其余的利用除法的計算方法和除法的性質(zhì)簡算.
解答:
解:24000÷125÷8
=24000÷(125×8)
=24000÷1000
=24;
4800÷50÷2
=4800÷(50×2)
=4800÷100
=48;
78000÷25÷4
=78000÷(25×4)
=78000÷100
=780;
56000÷14÷4
=56000÷(14×4)
=56000÷56
=1000;
1200÷(12×4)
=1200÷12÷4
=100÷4
=25;
7200÷(36×25)
=7200÷36÷25
=200÷25
=8;
7800÷(39×50)
=7800÷39÷50
=200÷50
=4;
48000÷(48÷125)
=48000÷48×125
=1000×125
=125000;
25×32×125
=25×4×(8×125)
=100×1000
=100000;
48×20×125
=8×125×(6×20)
=1000×120
=120000;
739×98+739
=739×(98+1)
=739×(100-1)
=739×100-739×1
=73900-739
=73161;
87×102
=87×100+87×2
=8700+174
=8874;
6500÷25÷4
=6500÷(25×4)
=6500÷100
=65;
960÷(24×8)
=960÷24÷8
=40÷8
=5;
4800÷64
=4800÷8÷8
=600÷8
=75;
1800÷36
=1800÷18÷2
=100÷2
=50;
1260÷42
=1260÷6÷7
=210÷7
=30;
24000÷48
=24000÷24÷2
=1000÷2
=500;
1890÷63
=1890÷9÷7
=210÷7
=30;
4700÷50
=470÷5
=94;
8000÷32
=8000÷8÷4
=1000÷4
=250;
9000÷36
=9000÷9÷4
=1000÷4
=250;
27000÷45
=27000÷9÷5
=3000÷5
=600;
43000÷86
=43000÷43÷2
=1000÷2
=500.
點(diǎn)評:整數(shù)混合運(yùn)算的關(guān)鍵是抓住運(yùn)算順序,注意利用數(shù)字特點(diǎn),靈活運(yùn)用適當(dāng)?shù)姆椒ê瓦\(yùn)算定律簡算.