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5/8" + 13/16"

Adding two fractions of an inch, exactly — the everyday jobsite arithmetic that a decimal calculator gets wrong. Reduced, carried, and shown in millimetres.

5/8" + 13/16" =
=1-7/16"
Sum
1-7/16"
Decimal inch
1.4375"
Millimetres
36.5125 mm
5/8" − 13/16"
-0-3/16"
The work

Over a common denominator

Put both over 16: 5/8 = 10/16 and 13/16 = 13/16. Add the tops: 10/16 + 13/16 = 23/16, which carries past one inch. Reduced, that's 1-7/16" (1.4375 inches). TapeMath tracks it as an exact fraction, so it lands dead on the tape mark.
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