4.7×4.7+4.7×43×0.47怎么巧?
2个回答

4.7×4.7+4.7×43×0.47

=4.7×4.7+4.7×4.3×4.7

=4.7×4.7×(1+4.3)

=4.7×(5-0.3)×(5+0.3)

=4.7×(25-0.09)

=(4+0.7)×(25-0.09)

=4×25-4×0.09+0.7×25-0.7×0.09

=100-0.36+17.5-0.063

=117.5-0.423

=117.077