In computing net income there shall be allowed as deductions all the ordinary and necessary expenses paid or incurred by the taxpayer during the income period in carrying on its trade or business, except United States income and excess profits taxes and the tax imposed by this chapter. Without limiting the generality of the foregoing there shall be allowed as deductions: a reasonable allowance for salaries and other compensation for personal services actually rendered; rent; repairs; bad debts; interest; taxes, except United States income and excess profits taxes and the tax imposed by this chapter; losses sustained and not compensated for by insurance or otherwise; depreciation; depletion of mines, oil and gas wells, and timber; amortization of assets; amortization of premiums on “securities” as defined in § 44-14-2(5)(ii); and contributions to any corporation, association, or fund organized and operated exclusively for religious, charitable, scientific, literary, or educational purposes, no part of the net earnings of which inures to the benefit of any private shareholder or individual.