Answer: the answer is: 54857510
Explanation:
What i had just did was i just broke the equation into 2 parts: so i did first (4 + 78908 + 54732927 - 7) which gave me 54811832. Then i did the next part which was adding 45678 in the mix ( 54811832 + 45678 = 54857510) So, the number from which you are left with is 54857510.
((TIP: Next time when you see problems like this, break them down into smaller equations so it will be much easier for you to solve, and its much more quicker and less harsh on your brain rather then just trying to do in all in one shot))
~i hope this has helped you out, have a gr8 day/ night my friend!~ :-)