72*2.07-1.8*3.6 和6.8*16.8+19.3*3.2
2个回答

72*2.07-1.8*3.6

=3.6x20x2.07-1.8x3.6

=3.6x(41.4-1.8)

=3.6x(40-0.4)

=3.6x40-3.6x0.4

=144-1.44

=142.56

6.8*16.8+19.3*3.2

=6.8x16.8+(16.8+2.5)*3.2

=6.8x16.8+16.8x3.2+2.5x3.2

=16.8x(6.8+3.2)+2.5x4x0.8

=16.8x10+10x0.8

=168+8

=176

如果本题有什么不明白可以追问,