Question

数学简算

9999*7778+3333*6666

5.6*69.32+138.64*0.05+693.2*0.43

1234567891的2次方-1234567890*1234567892

谢谢
讲一讲过程

Answer 1

9999*7778+3333*6666
=9999*7778+9999*2222
=9999*(7778+2222)
=9999*10000
=99990000

5.6*69.32+138.64*0.05+693.2*0.43
=5.6*69.32+69.32+69.32*4.3
=69.32*(5.6+1+3.4)
=69.32*10
=693.2

1234567891^2-1234567890*1234567892
=1234567891^2-(1234567891-1)*(1234567891+1)
=1234567891^2-1234567891^2+1
=1

Answer 2

9999*7778+3333*6666
=9999*7778+3333*3*2222
=9999*7778+9999*2222
=9999*(7778+2222)
=9999*10000
=99990000

5.6*69.32+138.64*0.05+693.2*0.43
=6932*0.056+(6932*0.02)*0.05+6932*0.043
=6932*(0.056+0.001+0.043)
=6932*0.1
=693.2

1234567891的2次方-1234567890*1234567892
=1234567891的2次方-(1234567891-1)*(1234567891+1)
=1234567891的2次方-1234567891的2次方+1
=1

Answer 3

99990000.
693.2.
1.