1)2-5-4+12=2-(+5)-4+12=2+(-5)-4+12=
=-(5-2)-4+12=(-3)-(+4)+12=(-3)+(-4)+12=
=-(3+4)+12=(-7)+12=+(12-7)=5
2)
-4+6+3-12=(6-4)+3-12=2+3-12=5-12=
=-(12-5)=-7
3)
4-7-3+14=-(7-4)-3+14=-3-3+14=-(3+3)+14=
=-6+14=+(14-6)=8
1)2-5-4+12=2-(+5)-4+12=2+(-5)-4+12=
=-(5-2)-4+12=(-3)-(+4)+12=(-3)+(-4)+12=
=-(3+4)+12=(-7)+12=+(12-7)=5
2)
-4+6+3-12=(6-4)+3-12=2+3-12=5-12=
=-(12-5)=-7
3)
4-7-3+14=-(7-4)-3+14=-3-3+14=-(3+3)+14=
=-6+14=+(14-6)=8