His patio needs 56 stones because 8 multiplied by 7 equals 56. So if the paving stones are sold in batches of 12 (a dozen is equal to 12) then we need to find how many times 12 goes into 56. 12 cannot go into 56 evenly, but 12x5=60 which will be more than enough stones for Eric's patio. So Eric will need 5 batches of paving stones for his patio.