$$ - \pi $$

$$ \pi $$

$${\pi \over 2}$$

1

equivalent to $${ \sim p \leftrightarrow q}$$

a tautology

a fallacy

equivalent to $${p \leftrightarrow q}$$

833

437

$${{437} \over 4}$$

$${{833} \over 4}$$

A screw gauge having 100 divisions in the circular scale and pitch as 1 mm.

A screw gauge having 50 divisions in the circular scale and pitch as 1 mm.

A meter scale.

A vernier calliper where the 10 divisions in vernier scale matches with 9 division in main scale and main scale has 10 divisions in 1 cm.