Transum Shop ::  Laptops aid Learning ::  School Books ::  Tablets ::  Educational Toys ::  STEM Books

Transum Software

Mental Strategies

Practise your mental arithmetic skills and learn some new strategies with this self marking exercise.

Level 1 Level 2 Level 3 Level 4 Description Help More...
No calculator

This is level 1: mental strategies for addition. Click on the blue question mark buttons for strategy suggestions.

45 + 15

Correct Wrong

68 + 49

Correct Wrong

43 + 73

Correct Wrong

65 + 45

Correct Wrong

50 + 50

Correct Wrong

97 + 99

Correct Wrong

97 + 98

Correct Wrong

90 + 80

Correct Wrong

110 + 110

Correct Wrong

25 + 34 + 75

Correct Wrong

140 + 150

Correct Wrong

143 + 129

Correct Wrong

150 + 150

Correct Wrong

165 + 166

Correct Wrong

46 + 45 + 54

Correct Wrong

189 + 191

Correct Wrong

191 + 209

Correct Wrong

215 + 216

Correct Wrong


This is Mental Strategies level 1. You can also try:
Level 2 Level 3 Level 4


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.

This web site contains over a thousand free mathematical activities for teachers and pupils. Click here to go to the main page which links to all of the resources available.

Please contact me if you have any suggestions or questions.

Email address

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 6 May 'Starter of the Day' page by Natalie, London:

"I am thankful for providing such wonderful starters. They are of immence help and the students enjoy them very much. These starters have saved my time and have made my lessons enjoyable."

Comment recorded on the 14 September 'Starter of the Day' page by Trish Bailey, Kingstone School:

"This is a great memory aid which could be used for formulae or key facts etc - in any subject area. The PICTURE is such an aid to remembering where each number or group of numbers is - my pupils love it!

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

Polygon Pieces

Polygon Pieces

Arrange the nine pieces of the puzzle on the grid to make the given polygon. Level one is for those learning the names of shapes while other levels are for those who like a challenge!


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:


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.


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 should go offline for whatever reason, there are mirror sites at and that contain most of the resources that are available here on

When planning to use technology in your lesson always have a plan B!

Do you have any comments? It is always useful to receive feedback and helps make this free resource even more useful for those learning Mathematics anywhere in the world. Click here to enter your comments.


©1997-2022 WWW.TRANSUM.ORG

© Transum Mathematics 1997-2022
Scan the QR code below to visit the online version of this activity.

This is a QR Code

Description of Levels



Level 1 - Mental strategies for addition

Level 2 - Mental strategies for subtraction

Level 3 - Mental strategies for multiplication

Level 4 - Mental strategies for division

More Mental Methods including lesson Starters, visual aids, investigations and self-marking exercises.

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.

Log in Sign up

Curriculum Reference

See the National Curriculum page for links to related online activities and resources.

Extension Activity

Make up a ten-question mental arithmetic exercise for a friend. For each question you should secretly write down your prediction of which strategy they will use. You should include addition, subtraction, multiplication and division questions and your ten predictions should all be different.

Strategies to Add Mentally


35 + 9
= 35 + 10 − 1
= 45 − 1
= 44

Equivalent calculations

34 + 35
= 2 × 34 + 1
= 68 + 1
= 69

Partition both numbers

21 + 45
= 20 + 1 + 40 + 5
= 20 + 40 + 1 + 5
= 60 + 6
= 66

Partition second number

53 + 36
= 53 + 30 + 6
= 83 + 6
= 89

Common zeros

120 + 70
(12 + 7 = 19)
= 190


8 + 7 + 2
= 8 + 2 + 7
= 10 + 7
= 17

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.

Log in Sign up