21/50 times 16

21/50 * 16 = (21*16)/50

$${\mathtt{21}}{\mathtt{\,\times\,}}{\mathtt{16}} = {\mathtt{336}}$$

$${\frac{{\mathtt{336}}}{{\mathtt{50}}}} = {\frac{{\mathtt{168}}}{{\mathtt{25}}}} = {\mathtt{6.72}}$$