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### History and Feedback

#### Checkpoint description

Describe what's changed since the last checkpoint.

#### Christian Lawson-Perfect2 years, 8 months ago

Gave some feedback: Ready to use

#### Christian Lawson-Perfect2 years, 8 months ago

Saved a checkpoint:

I've reworded a bit.

Published this.

#### Elliott Fletcher2 years, 8 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 8 months ago

Gave some feedback: Has some problems

#### Chris Graham2 years, 8 months ago

Same issue here with "The amount of numbers in a sequence". Can you re-write anywhere else that we have this phrase please?

#### Elliott Fletcher2 years, 8 months ago

I've added steps to both parts

#### Elliott Fletcher2 years, 8 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 8 months ago

Elliott, can you add a step to both parts please, giving the formula and asking the student to identify $a_1$ and $d$

#### Chris Graham2 years, 8 months ago

Gave some feedback: Has some problems

#### Bradley Bush2 years, 9 months ago

Gave some feedback: Needs to be tested

#### Bradley Bush2 years, 9 months ago

Thank you for the feedback Christian,

• There was a slight error with the gap fills so I fixed that
• There was another error with the answer marking, so that's fixed too
• I've adjusted the advice as you recommended to include a table, but I've also left Hannah'smethod as an alternative, I'm not sure whether yu wanted it completely replaced or no so I've left it in.

#### Christian Lawson-Perfect2 years, 9 months ago

Gave some feedback: Has some problems

#### Christian Lawson-Perfect2 years, 9 months ago

Saved a checkpoint:

I've split this into two parts - why make up your own part headers when Numbas can do it for you? It's important to let the student submit their answer to one part before moving on to another.

This question could very easily have steps - identify the first term, identify the common difference, and then you can write down the formula.

I've added a sentence to the top of the advice describing what needs to be done. A "plan of action" like this makes it easier to follow the more detailed parts of the solution.

I'd work this out by drawing up a table:

 $n$ 1 2 3 $a_n$ 18 27 36 First differences 9 9

The formula is $a_n = a_1 + (n-1)d$. I can read off from the table that $a_1 = 18$ and $d = 9$.

There's a reason you're taught to do this stuff using tables at school - visually, you can see how $n$, $a_n$, and the common difference relate to each other as the sequence progresses. Without this, it can all seem like aimlessly shuffling numbers about.

#### Hannah Aldous2 years, 9 months ago

Gave some feedback: Needs to be tested

#### Elliott Fletcher2 years, 9 months ago

Gave some feedback: Has some problems

#### Elliott Fletcher2 years, 9 months ago

Main Parts

I think you should label each of the questions i) and ii) as you have done in the advice section

I think the expected answer in both of these questions is wrong, the answer that you have in the advice section is right, i think its just that you calculated the adding term using n=0 for the displayed answer.

i) where you have written nth term here it doesn't really display correctly, it looks like n^(t)h instead of n^th.

I think you should say "Our nth term will take the form 8n+b, where b is some constant"

ii) i think "them" should be "it"

I think you should say "Our nth term will take the form 5n+c, where c is some constant"

I think you use the wrong number when you say how much the original sequence is greater than the sequence for 5n by.

#### Vicky Hall2 years, 9 months ago

Gave some feedback: Has some problems

#### Vicky Hall2 years, 9 months ago

Change the question to 'find the formula for the $n$th term'. It would be good to have one increasing and one decrasing sequence to show that sometimes the $n$ coefficient is negative.

#### Hannah Aldous2 years, 9 months ago

Gave some feedback: Needs to be tested

#### Hannah Aldous2 years, 9 months ago

Created this as a copy of Finding the $n^{\text{th}}$ Term of a Quadratic Sequence.
Arithmetic sequences in an ice cream shop Ready to use Hannah Aldous 20/11/2019 14:36
Compute the partial sum of an arithmetic sequence Ready to use Hannah Aldous 20/11/2019 14:36
Finding the $n^{\text{th}}$ Term of a Quadratic Sequence Ready to use Hannah Aldous 20/11/2019 14:39
Identifying different types of sequences Ready to use Hannah Aldous 20/11/2019 14:40
Finding the formula for the $n^{\text{th}}$ term of linear sequences Ready to use Hannah Aldous 20/11/2019 14:39
Partial sum of an arithmetic sequence - birthday money Ready to use Hannah Aldous 20/11/2019 14:41
Find common difference in arithmetic sequences with gaps Ready to use Christian Lawson-Perfect 20/11/2019 14:39
Fill in the gaps in an arithmetic sequence Ready to use Christian Lawson-Perfect 20/11/2019 14:39
Write down and apply the formula for an arithmetic sequence. Ready to use Christian Lawson-Perfect 20/11/2019 14:46
Finding the Formula for the $n^{\text{th}}$ Term of Linear Sequences draft Chris Graham 20/07/2017 15:08
Inbbavathie's copy of Find common difference in arithmetic sequences with gaps draft Inbbavathie Ravi 24/07/2017 03:48
Find a particular term of a sequence using the given formula Ready to use Christian Lawson-Perfect 20/11/2019 14:38
Johan's copy of Write down and apply the formula for an arithmetic sequence. Has some problems Johan Maertens 02/08/2017 17:51
Finding the formula for the $n^{\text{th}}$ term of linear sequences draft steve kilgallon 19/11/2017 08:09
Compute the partial sum of an arithmetic sequence draft steve kilgallon 19/11/2017 08:11
Identifying different types of sequences draft Luis Hernandez 31/12/2018 01:38
Calcular la suma parcial de una sucesión aritmética Ready to use Luis Hernandez 14/01/2019 17:37
Identificando diferentes tipos de secuencias Ready to use Luis Hernandez 14/01/2019 13:19
Suma parcial de una secuencia aritmética - Cumpleaños Ready to use Luis Hernandez 14/01/2019 19:01
Encontrar la diferencia común en una Secuencia Aritmética Ready to use Luis Hernandez 14/01/2019 17:40
Encuentra un término particular de una secuencia usando la fórmula dada Ready to use Luis Hernandez 14/01/2019 17:48
Encontrar la fórmula para el término $n^{\text {th}}$ de una secuencia lineal Ready to use Luis Hernandez 14/01/2019 19:29
Simon's copy of Write down and apply the formula for an arithmetic sequence. draft Simon Thomas 25/02/2019 10:20
Simon's copy of Find common difference in arithmetic sequences with gaps draft Simon Thomas 25/02/2019 10:24
Simon's copy of Finding the formula for the $n^{\text{th}}$ term of linear sequences draft Simon Thomas 25/02/2019 10:30
Identifying different types of sequences draft Xiaodan Leng 10/07/2019 21:48
Write down and apply the formula for an arithmetic sequence. draft Xiaodan Leng 11/07/2019 01:48
Fill in the gaps in an arithmetic sequence draft Xiaodan Leng 11/07/2019 01:48
Find common difference in arithmetic sequences with gaps draft Xiaodan Leng 11/07/2019 01:49
Compute the partial sum of an arithmetic sequence draft Xiaodan Leng 11/07/2019 01:51
Partial sum of an arithmetic sequence - birthday money draft Xiaodan Leng 11/07/2019 01:54
Arithmetic sequences in an ice cream shop draft Xiaodan Leng 11/07/2019 01:55
Finding the formula for the $n^{\text{th}}$ term of linear sequences draft Xiaodan Leng 11/07/2019 01:55
Find a particular term of a sequence using the given formula draft Xiaodan Leng 11/07/2019 01:56
Finding the $n^{\text{th}}$ Term of a Quadratic Sequence draft Xiaodan Leng 11/07/2019 01:57
Paul's copy of Inbbavathie's copy of Find common difference in arithmetic sequences with gaps draft Paul Verheyen 05/10/2019 09:39
ibrahim's copy of Finding the formula for the $n^{\text{th}}$ term of linear sequences draft ibrahim khatib 21/12/2019 11:17

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