It's not for nothing that Mumbai has earned the reputation of being India's financial capital. With the Higher Secondary School Certificate (HSC) results due to be released on June 4, chances are that the highest number of students will veer towards a degree in commerce. After all, in Mumbai, it's about the money, honey. According to T A Shiware, dean of the commerce faculty at Mumbai University, 60-75% of degree college students opted for commerce over the last few years. Currently, there are over one lakh seats for FYBCom in colleges affiliated to the Mumbai University, and around 2.7 lakh in the entire undergraduate commerce faculty at the University. "Every year, the number of students opting for commerce increases by 10,000 to 20,000,'' added Shiware.
So, just what makes all that number crunching and tallying of balance sheets a hit with Mumbai's students? "I think the popularity of the course is due to the diverse career options available to students after a commerce degree,'' said Indu Shahani, principal of HR College of Commerce and Economics.
The days where people believed that a BCom was enough to land only a clerical job or a mid-level position in the banking sector are long gone. "There are a large number of career opportunities in financial markets as well as in fields such as insurance and accountancy,'' said Shahani.

Please explain to me the emboldened parts. Particularly I'm confused with the use "crunching" and "hit" here.
Source : http://timesofindia.indiatimes.com/Mumbai/Commerce-is-about-the-money-honey/articleshow/4605964.cms
number-crunching = accounting work; calculating
tallying = adding up
balance sheet = a financial statement of a company listing its assets and liabilities