The way you wrote it, using no parentheses at all, the PEMDAS rule
says that you mean this:
÷
where we do the division 
÷
first, then change it
to multiplication by the reciprocal of the second as ×
where when we cancel we get 
So we replace the ÷ by and now we have:
and the LCD is 80, so we have
We add the numerators and put it over the LCD as
or 
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But you may have forgotten about parentheses and ignored the PEMDAS rule
and meant this instead:
÷
If so we get LCD of 16 on the left and right
÷
÷
We know that when we divide a number by itself we get 1
or we can invert the second and multiply:
×
and after canceling, we get 1.
So if you ignored PEMDAS and parentheses, the answer is 1.
Edwin
