$${\frac{{\mathtt{28}}}{{\mathtt{42}}}} = {\frac{{\mathtt{2}}}{{\mathtt{3}}}} = {\mathtt{0.666\: \!666\: \!666\: \!666\: \!666\: \!7}}$$
Multiply by 100 to get a percent . . .
67% (nearest %) or 66 and 2/3%
% = out of 100
$${\frac{{\mathtt{28}}}{{\mathtt{42}}}} = {\frac{{\mathtt{2}}}{{\mathtt{3}}}} = {\mathtt{0.666\: \!666\: \!666\: \!666\: \!666\: \!7}}$$
Multiply by 100 to get a percent . . .
67% (nearest %) or 66 and 2/3%
% = out of 100