Number theory

# Operations with rational numbers

## Keywords:

 $\frac{a}{b}+\frac{c}{d}=\frac{ad+bc}{bd}$ Addition $\frac{a}{b}-\frac{c}{d}=\frac{ad-bc}{bd}$ Subtraction $\frac{a}{b}·\frac{c}{d}=\frac{ac}{bd}$ Multiplication $\frac{a}{b}:\frac{c}{d}=\frac{ad}{bc}$ Division