What is 90% written as a decimal rounded to the thousandths place.

Percents as decimals are that number divided by 100. The rule is to move the decimal 2 places to the left.

.9

.3

1.159

.09

.07

.65

.003

4.45

edit:

None need to be rounded so do you mean given to the thousandth place? In that case the thousandth is 3 decimal slots places to the left so like this:

.900

.300

1.159

.090

.070

.650

.003

4.450