Your speech-to-text output needs a bit of editing, it seems. We assume the fractions given are intended to be 1/8, 2/5, and 3/10. The sum of these is
... 1/8 + 2/5 + 3/10 = 5/40 +16/40 +12/40 = 33/40
The remaining fraction is 40/40 - 33/40 = 7/40.
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Some calculators will add these fractions directly.