25×0.75-(-25)×0.5+25×(-0.25)

问题描述:

25×0.75-(-25)×0.5+25×(-0.25)
要过成

25×0.75-(-25)×0.5+25×(-0.25)
=75X0.25+50X0.25-25X0.25
=100X0.25
=25