2.75+.003+.158=

Answer 1

Make sure you "line up" the decimal points before you add.

2.75
0.003
0.158

What do you get?

Answer 2

I copied and pasted your problem into the Google search box --

2.75 + .003 + .158 = 2.91100

Answer 3

That first one could be written 2.750 if it makes it clearer to you.

Answer 4

2.911