< **1** 2 >

### Multiplication sign

The multiplication sign (×) is very old. It comes from India, where it was created after the frequent use of cross-multiplication, as in

where you start to calculate from top left to bottom right and then from bottom left to top right . This results in a movement that looks like a cross .

##### Explanation

Everybody knows the multiplication tables, and so you know immediately the outcome of

Often you don't even have to write a multiplication sign, because everything is clear enough, as with

and you must therefore describe it as: *x* times *x* plus 4. Also the simple notation

is a multiplication, because it means: 3 times *x*. Rather tricky is

because here you multiply 156 with √6 and with *x*. But after some time you won't notice this anylonger and even a difficult term poses no problems, just look at

##### Other notations

Mathematicians prefer to write the multiplication sign as a point, to avoid confusion with the letter *x*, so

x·xinstead ofx×x

Sometimes you must use an asterisk (∗) because a point has the meaning of 'decimal point', and then you get

On calculators, smartphones and tablets you will normally see a × key, sometimes also a ∗ key.