1) 4,7-(-2)-(1,5)=5,2
1. 4,7-(-2)=4,7+2=6,7
2. 6,7-1,5=5,2
2) 1 2/9- 1 1/3 + 1 5/18=1 1/6
1. 1 2/9- 1 1/3=11/9-4/3=(11*1-4*3)/9=(11-12)/9=-1/9
2. -1/9+1 5/18=-7/9+23/18=(-1)*6+23*3/54=(-6+69)/54= 63/54=7/6=1 1/6
3) -7 2/5 + 4 1/6 - 1,2= - 4 13/30
-7 2/5 + 4 1/6= 4 1/6-7 2/5=25/6-37/5=(25*5-37*6)/30=(125-222)/30=-97/30
-97/30-1,2=-97/30-12/10=(-97)*1-12*3/30=-97-36/30=-133/30=-4 13/30