Find the value of expression:15/3+(7-3)^2

Ammonia molecules have three hydrogen atoms and one nitrogen atom. how many of each atom arein five molecules of ammonia

My hour hand points between the 8 and the 9 in 35 minutes it will be the next hour. what time is it ?

Last week , donnell practiced the piano 3 hours longer than marcus . together, marcus and donnell practiced the piano 11 hours . for how many hours did each young man practiced the piano