4 номер. Спасибо Буду презнателен.

а) 24-(-13)-(-12)=491. 24-(-13)= 24+13=372. 37-(-12)= 37+12=49б) -33-16-(-11)=-381. -33-16= -33+(-16)=-492. -49-(-11)= -49+11= -38в) -4,3-5,4-2,6= -12,31. -4,3-5,4= -4,3+(-5,4)= -9,72. -9,7-2,6= -9,7+(-2,6)= -12,3г) 4,7-(-2)-(-1,5)= 8,21. 4,7-(-2)= 4,7+2= 6,72. 6,7-(-1,5)= 6,7+1,5= 8,2д) 1 2/9 - 1 1/3 + 1 5/18= 1 3/181. 1 2/9 - 1 1/3= 1 2/9+(-1 1/3)= 1 2/9+(-1 3/9)= -1/92. -1/9 + 1 5/18= -2/18 + 1 5/18= 1 3/18е) -7 2/15 + 4 1/6 - 1,21. -7 2/15 + 4 1/6 = -6 34/30 + 4 5/30 = -2 29/302. -2 29/30 - 1,2= -2 29/30 + (-1 2/10) = -2 29/30 + (-1 6/30)= -3 35/30 = -4 5/30= -4 1/6