Math Elementary arithmetic Multiplication


The important rule of multiplication is:

$\text{factor} \cdot \text{factor}$ $=\text{product}$

At multiplication, the operands are designated as factor. The product is the result.


The sign

  • If both factors have the same sign the product is positive:
    $\color{green}{+} \cdot \color{green}{+} = \color{green}{+}$
    $\color{red}{-} \cdot \color{red}{-} = \color{green}{+}$

  • If the factors have different signs the product is negative:
    $\color{green}{+} \cdot \color{red}{-} = \color{red}{-}$
    $\color{red}{-} \cdot \color{green}{+} = \color{red}{-}$

Mathematical laws

If $a$, $b$ and $c$ are rational numbers, you have to consider these following mathematical laws: