Why is prepaid rent subtracted from the book income (in order to get taxable income) ? Isn't prepaid rent a deferred tax asset and is already recognized as an expense for tax purposes, right ? Can you please explain what I am incorrect about and why you would subtract it from book income to get taxable income.

At the beginning of 2015; Elephant, Inc. had a deferred tax asset of $10,000 and a deferred tax liability of $15,000. Pre-tax accounting income for 2015 was $750,000 and the enacted tax rate is 40%. The following items are included in Elephants pre-tax income:

Interest income from municipal bonds	$ 60,000
Accrued warranty costs, estimated to be paid in 2016	$130,000
Operating loss carryforward	$ 95,000
Installment sales revenue, will be collected in 2016	$ 65,000
Prepaid rent expense, will be used in 2016	$ 30,000