Think of a Number

Instructions Try your best to answer the questions above. Type your answers into the boxes provided leaving no spaces. As you work through the exercise regularly click the "check" button. If you have any wrong answers, do your best to do corrections but if there is anything you don't understand, please ask your teacher for help. When you have got all of the questions correct you may want to print out this page and paste it into your exercise book. If you keep your work in an ePortfolio you could take a screen shot of your answers and paste that into your Maths file.

	You are learning this because future ideas are built on previous ideas and the more ideas you learn the more power you have to learn anything, ever! The world's best football player engages in rigorous training, practicing skills repeatedly to prepare for the big game. While the specific actions rehearsed during these exercises are rarely needed in the match, the very process of performing these drills enhances their overall prowess as a top player. more...	More Activities: Maths Map Go Maths Games Puzzles Times Tables TablesMaster iPad Maths Investigations Exam Questions
Mathematicians are not the people who find Maths easy; they are the people who enjoy how mystifying, puzzling and hard it is. Are you a mathematician? Comment recorded on the i asp?ID_Top 'Starter of the Day' page by Ros, Belize: "A really awesome website! Teachers and students are learning in such a fun way! Keep it up..." Comment recorded on the 28 September 'Starter of the Day' page by Malcolm P, Dorset: "A set of real life savers!! Keep it up and thank you!"		Each month a newsletter is published containing details of the new additions to the Transum website and a new puzzle of the month. The newsletter is then duplicated as a podcast which is available on the major delivery networks. You can listen to the podcast while you are commuting, exercising or relaxing. Transum breaking news is available on Twitter @Transum and if that's not enough there is also a Transum Facebook page.
Featured Activity Roman Numerals Quiz You may understand our number system better by learning about another number system. A basic knowledge of Roman numerals will allow you to complete level one of this self marking quiz. Beyond level one will require a little more!	Answers There are answers to this exercise but they are available in this space to teachers, tutors and parents who have logged in to their Transum subscription on this computer. A Transum subscription unlocks the answers to the online exercises, quizzes and puzzles. It also provides the teacher with access to quality external links on each of the Transum Topic pages and the facility to add to the collection themselves. Subscribers can manage class lists, lesson plans and assessment data in the Class Admin application and have access to reports of the Transum Trophies earned by class members. If you would like to enjoy ad-free access to the thousands of Transum resources, receive our monthly newsletter, unlock the printable worksheets and see our Maths Lesson Finishers then sign up for a subscription now: Subscribe
Go Maths Learning and understanding Mathematics, at every level, requires learner engagement. Mathematics is not a spectator sport. Sometimes traditional teaching fails to actively involve students. One way to address the problem is through the use of interactive activities and this web site provides many of those. The Go Maths page is an alphabetical list of free activities designed for students in Secondary/High school. Maths Map Are you looking for something specific? An exercise to supplement the topic you are studying at school at the moment perhaps. Navigate using our Maths Map to find exercises, puzzles and Maths lesson starters grouped by topic.
Teachers
If you found this activity useful don't forget to record it in your scheme of work or learning management system. The short URL, ready to be copied and pasted, is as follows:	Alternatively, if you use Google Classroom, all you have to do is click on the green icon below in order to add this activity to one of your classes.	It may be worth remembering that if Transum.org should go offline for whatever reason, there is a mirror site at Transum.info that contains most of the resources that are available here on Transum.org. When planning to use technology in your lesson always have a plan B!

For Students:

For Teachers:

For All:

Transum.org is a proud supporter of the kidSAFE Seal Program

Example

Daniel says 'If I double my number and add 6 the answer is 30'

Method 1 - Work backwards

Start at the end of the sentence with the answer 30 and undo all of the operations Daniel performed on his number in reverse order.

30 minus 6 then divide by two

The number Daniel was thinking about was 12

Method 2 - Form and solve an equation

Let the number that Daniel is first thinking of be n.

2n + 6 = 30

Subtract 6 from both sides

2n = 24

Divide both sides by 2

n = 12

The number Daniel was thinking about was 12

Don't wait until you have finished the exercise before you click on the 'Check' button. Click it often as you work through the questions to see if you are answering them correctly. You can double-click the 'Check' button to make it float at the bottom of your screen.

Answers to this exercise are available lower down this page when you are logged in to your Transum account. If you don’t yet have a Transum subscription one can be very quickly set up if you are a teacher, tutor or parent.

\( \times 2\) \(+2\) \(28\) William says: 'I think of a number. I double my number and add 2 the answer is 28' What number was William first thinking of?	Working:
David says: 'I am also thinking of a number. If I multiply my number by 2 and add 6 the answer is 40' What number was David first thinking of?	Working:
Nicholas says: 'I think of a number. I multiply my number by 3 and add 4 the answer is 52' What number was Nicholas first thinking of?	Working:
James says: 'Can you guess what number I am thinking of if when I multiply it by 6 and add 2 the answer is 44?' What number was James first thinking of?	Working:
John says: 'If I divide my number by 5 and add 2 the answer is 5' What number was John first thinking of?	Working:
Jonathan says: 'If I multiply my number by 3 then add 5 then add 4 then add 3 the answer is 36' What number was Jonathan first thinking of?	Working:
Samuel says: 'I am thinking of my favourite number. If I add 8 to my number then divide the result by 2, the answer is 23' What number was Samuel first thinking of?	Working:
Christian says: 'My plan was to add 5 to my number then multiply the result by 4. Then I multiplied the result by 3 and finally subtracted 5. The answer is 151' What number was Christian first thinking of?	Working:
Noah says: 'I decided to add 5 to my number then multiply the result by 3, After that I subtracted 6 then doubled the result. The answer is 54' What number was Noah first thinking of?	Working:
Dylan says: 'If I multiply my number by 4 and subtract 6 then multiply the result by 2, the answer is 2 less than 102' What number was Dylan first thinking of?	Working:

Think of a Number

Ten students think of a number then perform various operations on that number. You have to find what the original numbers were.

Menu Level 1 Level 2 Level 3 Level 4 Help More

Instructions

More Activities:

Featured Activity

Roman Numerals Quiz

Answers

Go Maths

Maths Map

Teachers

Description of Levels

Curriculum Reference

Example

Method 1 - Work backwards

Method 2 - Form and solve an equation