This is not a quiz.

Adding (and subtracting) decimals are the same as adding (and subtracting) fractions.

You add (or subtract) tenths to tenths, hundredths to hundredths, thousandths to thousandths, etc.

What that means is you must line up the decimal point so that the place values line up.

For example, I'll show you how I solve 306.27 - 10.94

306.27

- 10.94

295.33

Check my work - I'm pretty sure it's correct.