简便运算数学题1.9999×2222+3333×33342.0.5×236×59/1193.238÷238又239/2384.125又1/20÷415.(1/2+1/3+.+1/1997)×(1+1/2+1/3+.+1/1996)-(1/2+1/3+.+1/1997)×(1/2+1/3+.+1/1996)

问题描述:

简便运算数学题
1.9999×2222+3333×3334
2.0.5×236×59/119
3.238÷238又239/238
4.125又1/20÷41
5.(1/2+1/3+.+1/1997)×(1+1/2+1/3+.+1/1996)-(1/2+1/3+.+1/1997)×(1/2+1/3+.+1/1996)

1、即9999×2222+3333×3333+3333=9999×2222+9999×1111+3333
=9999*3333+3333=33330000
2、=118×59/119=(119*59)/119-59/119=59-59/119=58又60/119
3、=238÷【(238×238+239)/238】=238×238/(238×238+239)
4、=125/41+1/20÷41
=3+2/41+(1/20)/41=3+1/41×(2+1/20)=3+1/41×(41/20)
=3又1/20
5、=(1/2+1/3+.....+1/1997)×1+(1/2+1/3+.....+1/1997)×(1/2+1/3+.....+1/1996)-(1/2+1/3+.....+1/1997)×(1/2+1/3+.....+1/1996)
=1/2+1/3+.....+1/1997 即用乘法分配率,后面的相减为0

9999×2222+3333×3334
=3333×3×2222+3333×3334
=3333×(6666+3334)
=3333×10000
=33330000
0.5×236×59/119
=118×59/119
=(119-1)×59/119
=119×59/119-59/119
=59-59/119
=58又60/119
设1/2+1/3+.....+1/1996=A
原式=(A+1/1997)*(1+A)-(1+A+1/1997)*A
去括号=A+A的平方+1/1997+1/1997A-A-A的平方-1/1997A
=1/1997

1.原式=3*3333*2222+3333*3334=6666*3333+3333*3334 =(6666+3334)*3333=10000*3333=333300002.原式=2*59*59/119=118*59/119=59*118/1193.原式=238*1/(238*239)=238/(238*239)=2394.原式=2501/20/4...

1.9999×2222+3333×3334=9999×2222+3333×
(3333+1)=1111[(9×2)+(3×3+1)]=31108
2.0.5×236×59/119=118×59/119=(119-1)×59/119=59-59/119