###Human: Anna puts three slices of ham in each sandwich. If she has 31 slices of ham, how many more slices of ham does she need to make 50 ham sandwiches?, ### Assistant: Anna needs 3 x 50 = 150 slices of ham to make 50 sandwiches.
Anna needs 150 - 31 = 119 more slices of ham 
 So the answer is :  119