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# Mental Strategies

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

##### Level 1Level 2Level 3Level 4DescriptionHelpMore...

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

 45 + 15? 68 + 49? 43 + 73? 65 + 45? 50 + 50? 97 + 99? 97 + 98? 90 + 80? 110 + 110? 25 + 34 + 75? 140 + 150? 143 + 129? 150 + 150? 165 + 166? 46 + 45 + 54? 189 + 191? 191 + 209? 215 + 216?
Check

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

## 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.

## Transum.org

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.

## More Activities:

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!
Thanks"

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#### 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!

## Answers

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## 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 are mirror sites at Transum.com and Transum.info that contain most of the resources that are available here on Transum.org.

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.

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Scan the QR code below to visit the online version of this activity.

https://Transum.org/go/?Num=829

## Description of Levels

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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.

## 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

34 + 35
= 2 × 34 + 1
= 68 + 1
= 69

### Partition both numbers

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

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

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

### Reordering

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.

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