Answer :
The easiest way would to write it down the page, line up the decimals and add straight down.2.911
first you put 2.75 on the top and put .003 and line up the decimals so it is the right answer then you add it up then once you are done and you have solved 2.75 + .003 you get 2.753 then you add 2.753 to .158 and you get 2.911.