1) -4*(-5)-(-30):6 = 20-(-5)=25
2) 15:(-15)-(-24):8 = -1-(-3) = -1+3=2
3) -8*(-3+12):36+2 = -8*9:36+2 = -72:36+2 = -2+2=0
4) 2,3*(-6-4):5 = 2,3*(-10):5=2,3*(-2)=*4,6
5) -21+(-3-4+5):(-2)=-21-2:(-2)=-21+1=-20
4/5-11/15=1/15 1/15*5/11=1/33 8/21+8/7=32/21 7/88*32/21=14/33 1/4+7/12 =5/6 3/7*5/6=5/14
45: (72 : 18)+120 : 8
72 : 18=4
48/4=11,25
120:8=15
11,25+15= 26,25