what is 3/7 times 4/5

$${\frac{{\mathtt{3}}}{{\mathtt{7}}}}{\mathtt{\,\times\,}}\left({\frac{{\mathtt{4}}}{{\mathtt{5}}}}\right) = {\frac{{\mathtt{12}}}{{\mathtt{35}}}} = {\mathtt{0.342\: \!857\: \!142\: \!857\: \!142\: \!9}}$$

Well, for fractions, the numerators multiply and the denominators multiply.

So it would be:

(3x4)/(7x5)

=12/35