Falkirks

$${\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{1}} = {\mathtt{3}}$$

$$\left(-{\mathtt{3}}\right){\mathtt{\,\times\,}}\left(-{\mathtt{1}}\right) = {\mathtt{3}}$$

$$\left(-{\mathtt{3}}\right){\mathtt{\,\times\,}}{\mathtt{1}} = -{\mathtt{3}}$$

$${\mathtt{3}}{\mathtt{\,\times\,}}\left(-{\mathtt{1}}\right) = -{\mathtt{3}}$$

So, ±3 x ±1 = 3, -3

$${\mathtt{699\,954}}{\mathtt{\,\times\,}}\left({\frac{{\mathtt{73.9}}}{{\mathtt{100}}}}\right) = {\mathtt{517\,266.006}}$$

$${\sqrt{{\mathtt{68\,784\,678\,546.854\: \!685\: \!4}}}} = {\mathtt{262\,268.333\: \!099\: \!622\: \!771\: \!442\: \!4}}$$