This study notes covers Worked Example 3: Decreasing Sequence within nth Term for GCSE Mathematics. Revise nth Term in Algebra for GCSE Mathematics with 11 exam-style questions and 4 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 7 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 7
Practice
11 questions
Recall
4 flashcards
Worked Example 3: Decreasing Sequence
Find the nth term of: 20, 17, 14, 11, 8, ...
Step 1 Find the common difference
17 − 20 = −3
Common difference d = −3
Step 2 Start the formula
nth term starts with −3n
Step 3 Compare and adjust
−3n gives: −3, −6, −9, −12...
Sequence is: 20, 17, 14, 11...
20 − (−3) = 23, so add 23
Answer: nth term = −3n + 23 (or 23 − 3n)