Packing cherries

This task is about solving maths problems using multiplication and division.
illustration: box of cherries
Workers picked boxes of cherries in the Heremia's orchard and packed them into cartons.
 

Question 1Change answer

a)  Yesterday 3 workers picked 12 boxes of cherries each.
The boxes were then packed into cartons for the market, with 4 boxes in each carton.
How many cartons were packed for the market?  cartons

Question 2Change answer

b)  If 3 workers picked 16 boxes of cherries each, how many cartons would be packed?
      cartons.

Question 4Change answer

c)  If 5 workers picked 12 boxes of cherries each, how many cartons would be packed?
      cartons

Question 6Change answer

d)  If 21 full cartons were sent off to the market, how many boxes were needed to fill all these cartons?
      boxes