Question

小学数学简便计算

72*26+24*28。 999*999+1999 9999*2222+3333*3334。有谁知道这些题目怎么写吗？？

Answer 1

1.     72x26+24x28=72x26+26x28--2x28

                             =26x100--56

                             =2600--56

                                 =2544.

2.        999x999+1999=999x999+999+1000

                                  =999x1000+1000

                                  =1000x1000

                                  =1000000.

3.       9999x2222+3333x3334=9999x2222+3333x(3333+1)

                                                =9999x2222+9999+3333

                                                =9999x3333+3333

                                                =3333x10000

                                                =33330000.

追问

第三题的2222去哪了？

Answer 2

72×26+24×28
=72×26+（24+2）×28-2×28
=（72+28）×26-56
=2600-56
=2544

999×999+1999
=999×（999+1）+1999-999
=999000+1000
=1000000

9999×2222+3333×3334。
=3333×3×2222+3333×3334
=3333×（6666+3334）
=33330000

Answer 3

72*26+24*28
=24*3*26+24*28
=24*(78+28)
=24*106
=24*100+24*6
=2400+144
=2544
9999*2222+3333*3334
=3333*3*2222+3333*3334
=3333*(6666+3334)
=3333*10000
=33330000

999*999+1999
=999*(1000-1)+(1000+999)
=999000-999+1000+999
=999000+1000
=1000000

Answer 4

72*26+24*28
=(72+28)*(26+24)
=100*50
=5000

999×999+1999
=(1000-1)×999+1999
=999000-999+1999
=999000+（1999-999）
=999000+1000
=1000000

3*3333*2222+3333*3334
=3333*（3*2222）+3333*3334
=3333*6666+3333*3334
=3333*（6666+3334）
=3333*10000
=33330000

Answer 5

999*999+1999 =999*（1000-1）+1999=999*1000-999+1999=999000+1000=1000000