Multiple choice Find out the wrong number in the following number series. 15, 17, 21, 27, 29, 33 29 21 33 27 17 Reveal answer Fill a bubble to check yourself C Correct answer Explanation The series should follow the pattern +2, +4, +6, +8, +10: 15, 17, 21, 27, 35, 45. The term 29 breaks this pattern as it should be 35, making 33 the wrong number.