I got the answers. Please check it it's correct. Thanks!

Carry out the following operations. Express the answer to the proper number of significant figures.

1.) (4.35x10e3)+(26.711x10e4)+(8.09x10e2)
My answer is 2.7227 x10e5

2. (6.180x10e4)x(2.40x10e-3)
My answer is 1.4832 x10e-6

3. 7.5x10e5 divided by 4089x10e-2
My answer is 1.8349x10e3

Are my answers right? I mean the number of significant figures? Just checking! Thanks