Answer:
80.00 mL
Step-by-step explanation:
Let's consider the following addition.
22.33 mL + 55.666 mL + 0.001 mL
22.33 mL has 4 significant figures.
55.666 mL has 5 significant figures.
0.001 mL has 1 significant figure.
For addition and subtraction, we look at the places to the decimal point. Add or subtract in the normal fashion, then round the answer to the least number of places to the decimal point of any number in the problem.
22.33 mL + 55.666 mL + 0.001 mL
77.997 mL ≈ 80.00 mL