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13/16" + 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.

13/16" + 13/16" =
=1-5/8"
Sum
1-5/8"
Decimal inch
1.625"
Millimetres
41.275 mm
13/16" − 13/16"
0"
The work

Over a common denominator

Put both over 16: 13/16 = 13/16 and 13/16 = 13/16. Add the tops: 13/16 + 13/16 = 26/16, which carries past one inch. Reduced, that's 1-5/8" (1.625 inches). TapeMath tracks it as an exact fraction, so it lands dead on the tape mark.
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