How many Suns are there in our galaxy?
There are a lot of partial answers here, and all of them are right based upon their parameters.
The biggest problem is that only a fraction of our galaxy is visible. 20 degrees to each side of the galactic core is fully obscured, and 70 to 90 degrees is partially obscured by dust, so all of our numbers are estimates based upon the number and densities that we can see.
Thanks for the A2A.
It depends on your definition of a Sun.
If you define a Sun as the star we orbit around, then there can be only one.
If you define it as a star with planet(s), then you're talking in the tens of millions (although many planetary systems would be too far away to detect by current methods, so only a ballpark estimate is possible).
However, if by Sun you mean star, then in the Milky Way there are between ten and forty billion of them, of all different sizes, temperatures, colours and even shapes. (Some stars rotate on their axes so quickly that they're actually rugby ball-shaped instead of spherical!)
There is one Sun, but there are a lot of stars, which also happen to be suns.
Actually it is very difficult to say with any precision how many stars there are in the Milky Way galaxy, as there are so many it is impossible to count.
So the way we get a number is to infer how much mass the galaxy has, which clever astronomers can do, and from that calculate how many stars there are.
The mass estimate generally considered about right is around 100 billion times the mass of our Sun. If you assume a lot of stars are larger than ours, and a lot are smaller, it may be a fair assumption that on average they have the same mass as the Sun, therefore there are 100 billion stars.
Whatever the answer (and it could be neither of the above!) we know for sure it is a very big number. And that is in just one of the now estimated 2 trillion galaxies!
There are numerous sources for estimates - here is a simple page...