Multiple choice Find out the wrong number in the following number series. 10, 5, 5, 20, 40, 320 10 20 40 320 5 Reveal answer Fill a bubble to check yourself B Correct answer Explanation The series follows the pattern ÷2, ×1, ×2, ×4, ×8: 10÷2=5, 5×1=5, 5×4=20 (should be ×2=10), 10×4=40 (should be ×4=40), 40×8=320. The term 20 should be 10 to maintain the pattern.