Count the digits following the decimal point to turn 0.5 as a fraction.
Five-tenths, or 0.5, is expressed as a fraction. Reason: It's one digit after the decimal point (which is the tenths place).
Then, you'd write it as 5/10, for five-tenths.
Then you would condense the group into: 1/2
For one thing, the number five divides by itself once, and it multiplies by 10 twice.
Five is also exactly half of ten, which is another way of looking at it.