1. 4,,5) 2. 1 2\9 - 1 1\3 + 1 5\18 3. -7 2\15 + 4 1\6 - 1,2

1) 4,7-(-2)-(-1,5)= 4,7+2+1,5= (4,7+1,5)+2=6,2+2=6,2+2,0=8,2.
2) 12\9 -11\3 +15\18 = 4\3-11\3 +5\6 =(2*4 -2*11 +1*5)\6 = (8-22+5)\6=
= (13-22)\6 = (-9)\6 =-3\2 = -1,5.
3) -7 2\15 + 4 1\6 - 1,2 =-7 2\15 + 4 1\6 - 1 1\5 = (-7+4-1) +( 2\15+1\6 -1\5)=
= -4+(-2*2+5*1-6*1)\30 = -4 +(-4+5-6)\30= -4 +(-5)\30=-4-1\6= -4 1\6/