(-63)×(2-302)-302×63
= (-63).2 +63.302 -302.63
= -126 +63.(302 -302)
= -126 +63.0
= -126
(-12)×78+(-12)×22
= (-12).(78 +22)
= (-12).100
= -1200
1345×(-15)+15×345
= 15.(-1345 +345)
= 15.(-1000)
= -15000
18×(-7)-7×(-38)
= (-7).(18 -38)
= (-7).(-20)
= 140
10×(-12)+28×(-10)+(-60)×10
= 10.(-12 -28 -60)
= 10.(-100)
= -1000