Adding decimals has steps to follow not like the whole number when adding, you can add it straight.
Given:
3.089 g and 0.074 52 g
The first step arranged the numbers and second lined up the decimal points when writing down and then simply add the numbers that lined up in the decimals points.
3.089
+ 0.07452
3 .16352
so, you can easily get the answer 3.16352 g.
