Răspuns:
10.
1/1-1/3=2/1×3=>1/1×3=1/2(1/1-1/3)
1/2(1/1-1/3+1/3-1)5+1/5-1/7+...1/2021-1/2023)=1/2(1-1/2023)
=1/2(2022/2023)=1011/2023=>c)
se reduc-cu+(-1/3+1/3)
11. 4m_____2zile___4ore/zi
2m______x______8ore/zi
1)4×2=2×x. x=4zile
2) verificare 2/4=4/8=1/2(A)=>4zile a)
