12+85= \frac{12+8}{5}= 512+8=
Let's begin by solving the numerator of the fraction, from left to right, according to the order of operations:
12+8=20 12+8=20 12+8=20
We should obtain the following exercise:
205=20:5=4 \frac{20}{5}=20:5=4 520=20:5=4
4