=(21-2+19)-(50-0.1)+(10+0.2)-3.5
=38-50+0.1+10+0.2-(3+0.5)
=(38-50+10-3)+(0.1+0.2-0.5)
=-5-0.2
=-5-1/5
=-(5+1/5)
=负5又5分之1
希望能帮你忙,懂了请采纳,
=(21-2+19)-(50-0.1)+(10+0.2)-3.5
=38-50+0.1+10+0.2-(3+0.5)
=(38-50+10-3)+(0.1+0.2-0.5)
=-5-0.2
=-5-1/5
=-(5+1/5)
=负5又5分之1
希望能帮你忙,懂了请采纳,