Explicație pas cu pas:
a) 1,5 + 3 = a
a= 4,5
b) 2/3 - 1 = a
a = (2-3)/3 = - 1/3
c) 2/3 × 3/5 - 1/2 = a
a = 6/15 - 1/2 = 2/5 - 1/2 = (4-5)/10 = - 1/ 10
d) 0,2 × 10/3 - 1/5 = 2/3 a
2/3 a = 2/10 × 10/3 - 1/5
2/3a = 2/3 - 1/5
2/3 a = (10-3)/15
2/3 a = 7/15
a = 7/15 : 2/3
a = 7/ 15 × 3/2
a = 7/10
