Răspuns:
20:{[10-4×4:(a-3×5)]+2}=2023 - 2018
20:{[10-4×4:(a-3×5)]+2}=5
[10-4×4:(a-3×5)]+2 = 20 : 5
[10-4×4:(a-3×5)]+2=4
10-4×4:(a-3×5)= 4-2
10-4×4:(a-3×5)=2
4×4:(a-3×5)=10-2
4×4:(a-3×5)=8
16:(a-3×5) = 8
a-3×5= 16 : 8
a-3×5=2
a-15 = 2
a = 2 + 15
a = 17