5−2×12+1= 5-2\times\frac{1}{2}+1= 5−2×21+1=
In the first stage of the exercise, you need to calculate the multiplication.
2×12=21×12=22=1 2\times\frac{1}{2}=\frac{2}{1}\times\frac{1}{2}=\frac{2}{2}=1 2×21=12×21=22=1
From here you can continue with the rest of the addition and subtraction operations, from right to left.
5−1+1=5 5-1+1=5 5−1+1=5
5