# How do you write the number 420000 in standard form?

##### 1 Answer

Jan 13, 2017

#### Explanation:

A number expressed in

#color(blue)"standard form"# is.

#color(red)(bar(ul(|color(white)(2/2)color(black)(axx10^n)color(white)(2/2)|)))#

#"where " -1<=a<10" and n is an integer"# We have to write 420000 as a number between 1 and 10

The decimal point in 420000 is at

#420000color(red)(•)# and we want

#4color(red)(•)20000# so that it is a value between 1 and 10To place the decimal point back to it's original position means moving it 5 places to the right, effectively multiplying by 100000

#rArr4.2xx100000=4.2xx10^5larr" in standard form"#