原题可知能是道28.9x61.5+111x6.15
=28.9x61.5+11.1x61.5
=(28.9+11.1)x61.5
=40x61.5
=2460
或者回就这样答做28.9x61.3+111x6.15
=28.9x61.3+111x6.13+111x0.02
=289x6.13+111x6.13+2.22
=400x6.13+2.22
=2452+2.22
=2454.22