小升初數(shù)學【簡便計算】專項訓練匯總一、乘法分配律(1.25-0.125)×8

(125+2.5)×0.8

3.72×3.5+6.28×3.5=1.25×8-0.125×8

=125×0.8+2.5×0.8

=3.5×(3.5+6.28)=10-1

=1+1

=3.5×10=9

(正用)

=2

(正用)

=35

(逆用)二、乘法交換律0.25×8.5×4

12.5×0.96×0.8

0.5×0.34×0.6=0.25×4×8.5

=12.5×0.8×0.96

=0.5×0.6×0.34=1×8.5

=10×0.96

=0.3×0.34=8.5

=9.6

=0.102三、乘法結(jié)合律4.36×12.5×8

0.95×0.25×4

0.75×50×0.4=4.36×(12.5×8)

=0.95×(0.25×4)

=0.75×(50×0.4)=4.36×100

=0.95×1

=0.75×20=436

=0.95

=15四、拆數(shù)+乘法結(jié)合律0.125×8.8

0.25×0.28

0.125×3.2×2.5=0.125×8×1.1

=0.25×4×0.07

=(0.125×8)×(0.4×2.5)=1×1.1

=1×0.07

=1×1=1.1

=0.07

=1小升初數(shù)學【簡便計算】專項訓練匯總五、把其中一個因數(shù)分成兩個數(shù)的和或差，再按乘法分配律0.8×100.1

3.65×10.1

0.32×403=0.8×(100+0.1)

=3.65×(10+0.1)

=0.32×(400+3)=0.8×100+0.8×0.1

=3.65×10+3.65×0.1

=0.32×400+0.32×3=80+0.08

=36.5+0.365

=128+0.96=80.08

=36.865

=128.96六、更改因數(shù)的小數(shù)點位置6.66×3.3+0.666×67

46×57+23×86

4.8×7.8+78×0.52=6.66×3.3+6.66×6.7

=46×57+46×43

=4.8×7.8+7.8×5.2=6.66×(3.3+6.1)

=46×(57+43)

=7.8×(4.8+5.2)=6.66×10

=46×100

=7.8×10=66.6

=4600

=78七、添加因數(shù)“1”56.5×99+56.5

9.7×99+9.7

4.2×99+4.2=56.5×99+56.5×1

=9.7×99+9.7×1

=4.2×99+4.2×1=56.5×(99+1)

=9.7×(99+1)

=4.2×(99+1)=56.5×100

=9.7×100

=4.2×100=5650

=970

=420小升初數(shù)學【簡便計算】專項訓練匯總125×(17×8)×4=125×8×4×17=1000×68=68000375×480+6250×48=480×(375＋625)=480×1000=48000025×16×125=25×2×8×125=50×1000=5000013×99=13×(100－1)=1300－13=128775000÷125÷15=75×1000÷125÷15=75÷15×1000÷125=407900÷4÷25=7900÷(4×25)=7900÷100=79150×40÷50=150÷50×40=3×40=1205600÷(25×7)=56×100÷25÷7=56÷7×100÷25=32210÷42×6=210÷7÷6×6=30÷6×6=3039600÷25=396×100÷25=396×4=1584小升初數(shù)學【簡便計算】專項訓練匯總321×81+321×19=321×(81+19)=321×100=3210027000÷125=27×1000÷125=27×8=216347+358+352+349=350×4－3+8+2－1=1400+6=14060.77÷35=0.77÷(7×5)=0.77÷7÷5=0.0224.2×101＝4.2×(100＋1)＝4.2×100＋4.2×1＝420＋4.2＝424.22.73×99＋2.73＝2.73×99＋2.73×1＝2.73×(