Question

How do you use the distributive property to find 9 x 99?

Answer 1

`9xx99=color(red)(891)`

Explanation:

`9xx99`
`color(white)("XXX")=9xx(90+9)`

`color(white)("XXX")=underbrace(9xx90) + underbrace(9xx9)color(white)("xxx")`...the distributive property

`color(white)("XXX")=810 +81`

`color(white)("XXX")=810`
`color(white)("XX=X")ul(+color(white)(".")81)`
`color(white)("XXXXX")891`

~~~~~~~~~~~~~~ OR ~~~~~~~~~~~~~~~~~~~~~~~~~

`9xx99`
`color(white)("XXX")=9xx(100-1)`

`color(white)("XXX")=underbrace(9xx100)-underbrace(9xx1)color(white)("xxx")`...the distributive property

`color(white)("XXX")=900 -9`

`color(white)("XXX")=891`

~~~~~~~~~~~~~ OR ~~~~~~~~~~~~~~~~~~~~~~~~~~

`9xx99`
`color(white)("XXX")=(10-1)xx99`

`color(white)("XXX")=underbrace(10xx99)-underbrace(1xx99)color(white)("xxx")`...distributive property

`color(white)("XXX")=990-99`

`color(white)("XXX")=891`