to the nearest thousandth.
Convert the first mixed number to a decimal.
Convert the second mixed number to a decimal. To make it easier to do that, we can find an equivalent fraction with a denominator that is a factor of 10.
Then add vertically, with the decimal points under each other. Add from the right to the left.
To approximate to the nearest thousandth, look at the digit in the ten thousandths place. 7 is equal to 5 or more, so increase the digit in the thousandths place by 1 and leave out the other digits to the right.