①-4.5+(-2.6)-(-7)
=-4.5-2.6+7
=-0.1
②-(-21)+(-13)-(-25)-(+28)-4
=21-13+25-28-4
=1
42-(+23)-(-31)+(-29)
=42-23+31-29
=21
④(-12)-(-18)+(-7)-(+15)
=-12+18-7-15
=-16
⑤73+(-219)-(+81)
=73-219-81
=73-300
=-227
①-4.5+(-2.6)-(-7)
=-4.5-2.6+7
=-0.1
②-(-21)+(-13)-(-25)-(+28)-4
=21-13+25-28-4
=1
42-(+23)-(-31)+(-29)
=42-23+31-29
=21
④(-12)-(-18)+(-7)-(+15)
=-12+18-7-15
=-16
⑤73+(-219)-(+81)
=73-219-81
=73-300
=-227