B=\(\frac{12+\frac{4}{3}-\frac{12}{37}-\frac{12}{53}}{3+\frac{1}{3}-\frac{3}{37}-\frac{3}{53}}:\frac{4+\frac{4}{17}+\frac{4}{19}+\frac{4}{2003}}{5+\frac{5}{17}+\frac{5}{19}+\frac{5}{2003}}\)
=\(\frac{12+\frac{12}{9}-\frac{12}{37}-\frac{12}{53}}{3+\frac{3}{9}-\frac{3}{37}-\frac{3}{53}}:\frac{4+\frac{4}{17}+\frac{4}{19}+\frac{4}{2003}}{5+\frac{5}{17}+\frac{5}{19}+\frac{5}{2003}}\)
=\(\frac{12\left(\frac{1}{1}+\frac{1}{9}-\frac{1}{37}-\frac{1}{53}\right)}{3\left(\frac{1}{1}+\frac{1}{9}-\frac{1}{37}-\frac{1}{53}\right)}:\frac{4\left(\frac{1}{1}+\frac{1}{17}+\frac{1}{19}+\frac{1}{2003}\right)}{5\left(\frac{1}{1}+\frac{1}{17}+\frac{1}{19}+\frac{1}{2003}\right)}\)
=\(4:\frac{4}{5}\)
=\(5\)