For infants and toddlers, just colour q-tips will be a fun activity as it encourages fine motor skills. Alternatives of the activity for older children would be to give each colour a numerical value to make equations. Ex. Yellow =5 and blue equals 2 red equals 7, _ + _ = 9 then they have to put blue q-tip and red q-tip to make a total to 9.
Also to colour q-tips, you could use paint instead of food colours or simply dip dried out unusable markers in small quantity of water.