Answer:
2
Step-by-step explanation:
Obtain the greatest common factor of both 12 and 10
Factors of 10 = 1, 2, 5, 10
Factors of 12 = 1, 2, 3, 4, 6, 12
From the above, the greatest common factor of 10 and 12 is 2
Hence, smallest number of pencils using the boxes is 2