•addition and subtraction…
•first add them up! don’t worry about sigfigs until the end!
•3.75 + 4.1 = 7.85
–you can only go to where all numbers have something to contribute, so can only go to 7.9
•3.987 + 4.60 = 8.587
–but can only go to 0.01, so 8.59