How to work this exercise 13.6 and 13.8?

ise 13.6: Johnny G's Cricket Shop made a cash purchase of office stationery for $590 on 73March 2005 On 30 June2005 it was found that $120 of stationery was not yet used. a Calculate the cost of stationery used during the period. b Prepare the adjusting and closing entries in the general journal on 30 June 2005. c Explain why the adjusting entry in b is necessary under accrual accounting. d Complete the stock of stationery account and the stationery expense account with all relevant entries