The rule for the nth term

Difficulty Starter · Set y96aoq

Write the rule for the nth term of each sequence, the n term first, like 3n + 2.

Fill in what you can and press Check. Nothing you type is sent anywhere.

1
9, 12, 15, 18, 21, …
2
7, 12, 17, 22, 27, …
3
1, 5, 9, 13, 17, …
4
4, 7, 10, 13, 16, …
5
3, 5, 7, 9, 11, …
6
9, 14, 19, 24, 29, …
7
2, 4, 6, 8, 10, …
8
3, 8, 13, 18, 23, …
9
8, 13, 18, 23, 28, …
10
1, 3, 5, 7, 9, …
11
4, 9, 14, 19, 24, …
12
10, 13, 16, 19, 22, …
13
2, 5, 8, 11, 14, …
14
3, 8, 13, 18, 23, …
15
2, 6, 10, 14, 18, …
16
8, 12, 16, 20, 24, …
17
4, 7, 10, 13, 16, …
18
5, 10, 15, 20, 25, …
19
8, 11, 14, 17, 20, …
20
10, 13, 16, 19, 22, …

What is in this set

The numbers in this set run from 1 to 30.
Every problem in it will ask for the rule rather than the next term.
A careful solution takes 3 written steps on average.
The mistake this set invites most often, in 100% of the problems: the first term was used as the number on the end.
Answers are a short answer exactly as the problem asks for it.

Drawing 240 problems from this page produced 40 different ones, 17% — so a sheet of 20 will come back to a problem you have seen — there are only so many sensible ones of this kind.

The same skill, harder or easier

We would put this in front of a grade 8 class. That is our judgement, not a standard, and it is printed here so you can disagree with it. Everything else we put in that year.