Question

99x55+78x44+78的简便计算？

Answer 1

原式=
99x55+78x（44+1）
=99x55+78x45=99*100-45）+78*45
=9900-99*45+78*45
=9900-21*45
=9900-900-45
=8955

Answer 2

99x55+78x44+78
=99x55 + 78x(44+1)
=99x55+78x(100-55)
=99x55+78x100-78x55
=(99-78) x55 + 7800
=21x55+7800
=1155+7800
=8955

Answer 3

78×55+78×44+78
=78×55+78×44+78
=78×（55+44+1）=7800

Answer 4

99×55+78×44+78
=99×55+78×(44+1)
=99×55+78×45
=99×(100-45)+78×45
=9900-99×45+78×45
=9900-45×(99-78)
=9900-45×21
=9900-45×20-45
=9000-45
=8955

Answer 5

原式=99×55+78×（44+1）
=99×55+78×45
=99×（100-45）+78×45
=99×100-99×45+78×45
=9900-（99-78）×45
=9900-21×45
=9900-20×45-1×45
=9900-900-45
=8945
找相同的因数，利用乘法分配律以及逆运算。