\(\frac{24-12.13}{12+4.9}=\frac{24-156}{12+36}=\frac{-132}{48}=\frac{-11}{4}\)
\(\frac{24-12\cdot13}{12+4\cdot9}=\frac{24-156}{12+36}=\frac{-132}{48}=\frac{-11}{4}\)
\(\frac{24-12.13}{12+4.9}\)
\(=\)\(\frac{12.2-12.13}{12.1+12.3}\)
\(=\frac{12\left(2-13\right)}{12\left(1+3\right)}\)
\(=\frac{2-13}{1+3}\)
\(=\frac{-11}{4}\)