If you are multiplying 5 times an even number: half the number you are multiplying by and place a zero after the number.
Multiplication is a mathmatical operation of scaling one nmber by another.
The numbers that are to be multiplied are called factors or multiplicands.
The Egptians method of multiplication of integers and fractions.
In China their multiplication calulations were wriien out in words, although the early chinese mathematicians employed in hand calculations involving muliplication and addition.