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5/16" + 9/16"

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

5/16" + 9/16" =

=0-7/8"

Sum

0-7/8"

Decimal inch

0.875"

Millimetres

22.225 mm

5/16" − 9/16"

-0-1/4"

The work

Over a common denominator

Put both over 16: 5/16 = 5/16 and 9/16 = 9/16. Add the tops: 5/16 + 9/16 = 14/16. Reduced, that's 0-7/8" (0.875 inches). TapeMath tracks it as an exact fraction, so it lands dead on the tape mark.

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