sophia bought 18 bags of pumpkin seeds. each bag contains 42 seeds. she plants half of the seeds. how many seds does she have left?

Johnny rode his bike to a friends house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was unable to play. what was his displacement for the total bike ride trip? what could you use as a reference point ? show the steps to solve this problem.