Final answer:
To estimate the total number of stars in the universe, you can multiply the number of galaxies by the average number of stars in each galaxy. The total number of stars in the universe is approximately 7.5*10^18 stars.
To estimate the total number of stars in the universe, we can multiply the number of galaxies by the average number of stars in each galaxy.
Given that there are approximately 5*10^9 galaxies and each galaxy has about 1.5*10^9 stars, we can calculate the total number of stars by multiplying these two values:
Total number of stars = (5*10^9) * (1.5*10^9) = 7.5*10^18 stars
Therefore, there are approximately 7.5*10^18 stars in the universe.