A number sequence is a list of numbers governed by a rule. The rule governing the numbers is used to determine other numbers that follow in the sequence.
A. In this sequence, the rule is to increase the difference between the previous two numbers by 1 and then add the result to the last number in the sequence.
(10 - 6) + 1 = 5
5 + 10 = 15
Also (15 - 10) + 1 6
6 + 15 = 21
B. The rule here is to subtract 1 from the negative difference between the previous two numbers in the sequence and then add the result to the last number in the sequence.
(2 - 5) - 1 = -4
2 + (- 4) = -2
Also, (-2 - 2) - 1 = -5
-2 + (-5) = -7
C. The rule here is to square the numbers starting from 1.
