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 2: mental strategies for subtraction. Click on the blue question mark buttons for strategy suggestions.

99 − 56
?

Correct Wrong

100 + 61 − 70
?

Correct Wrong

94 − 31
?

Correct Wrong

117 − 74
?

Correct Wrong

103 + 97 − 83
?

Correct Wrong

169 − 79
?

Correct Wrong

1416 − 707
?

Correct Wrong

252 − 128
?

Correct Wrong

246 − 116
?

Correct Wrong

2037 − 1014
?

Correct Wrong

2240 − 1113
?

Correct Wrong

275 − 130
?

Correct Wrong

2651 − 1347
?

Correct Wrong

306 − 159
?

Correct Wrong

372 − 177
?

Correct Wrong

370 − 196
?

Correct Wrong

362 − 189
?

Correct Wrong

254 + 202 − 214
?

Correct Wrong

Check

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

Why am I learning this?

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 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"

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!"

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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.

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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:

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

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https://www.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.

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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 Subtract Mentally

Adjusting

405 – 399
= 405 – 400 + 1
= 6

Reordering

58 + 47 – 38
=58 – 38 + 47
=20 + 47
= 67

Partitioning: counting on or back

276 – 153
= 276 – 100 – 50 – 3
= 123

Partitioning: bridging a multiple of 10

607 – 288
607 = 288 + 12 + 300 + 7
12 + 300 + 7 = 319

Counting forwards and backwards

124 – 47
count back 40 from 124
count back 4 to 80
count back 3 to 77

Adapted from The National Primary Strategies, UK Department for Education

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

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