The next number in the series is always found by adding the previous number to the number before it. So you calculate the number at position 3 by adding the number at position 2 to the number at position 1.

210 + 14 = 224

224 + 210 = 434

434 + 224 = 658

658 + 434 = 1092

1092 + 658 = 1750

1750 + 1092 = 2842