human
Fill in the blanks: 2, 4, 6, 8, 10, 12, [BLANK], 16, 18, 20
gpt
2, 4, 6, 8, 10, 12, 14, 16, 18, 20

The missing value is 14.

The number series is incremented by two on each step, so the blank value should be the next number after 12, which is 14.
human
Fill in the blanks: 20, 40, 60, 80, 100, 120, [BLANK], 160, 180, 200
gpt
The blank should be filled with the value of "140", as the above series increases by 20 each time.