99×78+33×66怎样简便计算

Question

要运用积不变的规律

Answer 1

你好，
解：原式=33*3*78+33*66
=33(3*78+3*22)
=99(78+22)
=99*100
=9900

Answer 2

99×78+33×66=99×78+（33×3）×22=99×78+99×22=99×（78+22）=99×100=9900

Answer 3

99×78+33×66
＝99×78+33×3×66÷3
＝99×78+99×22
＝99×（78+22）
＝99×100
＝9900

Answer 4

=33*3*78+33*66=33*234+33*66=33*300=9900

Answer 5

99*78+99*22=99*(78+22)=9900