Addition and subtraction problems�

Maths- Integers and Decimals

Mrs Booth

2

Exercise book or paper

Pencil

Image credit: Pixabay

In this lesson, you will need:

3

Starter quiz

Addition and subtraction with decimals

Addition and subtraction problems

Independent worksheet

Exit quiz

Keywords

Strategies - a carefully developed plan or method for achieving a goal or the skill in developing and undertaking such a plan or method.

​

Solve - to find an answer to a problem.

​

Addition - the process of calculating the sum of two or more addends.

​

Subtraction - the process of finding the difference between two numbers.

4

What different words are used in problems to identify addition and subtraction problems?

5

6

Mathematical vocabulary!

add

greater than

plus

altogether

sum

total

more than

increase

subtract

less than

minus

take away

less

difference

fewer than

decrease

How to use strategies to solve subtraction and addition problems.

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8

1693 + 6225

Is this a subtraction or an addition problem?

At a recent concert 1693 people bought the early bird ticket saving $50 on their tickets. Then 6225 people bought tickets at full price. How many people altogether bought tickets?

Round and adjust

9

1693

1700

+7

7920

6225

6220

-2

7918

-5

+

10

$50.00

$37.00

$36.24

+$0.76

+$3.00

$50.00

$13.76

$10.00

+$3.76

-$40.00

Lily buys a dress for $36.24. She pays with a $50 dollar note. How much change does she get?

$13.76

$13.75

$40.00

+$10.00

11

$50.00

$26.00

$25.95

+$0.05

+$4.00

$50.00

$24.05

$20.00

+$4.05

-$30.00

Lily buys two dresses; one costs $25.95 and she pays a total of $50. How much does the other dress cost?

$24.05

$30.00

+$20.00

12

Strategies

13

Which year had more males, and how many more males was there than the following year?

What steps are required to solve the problem below?

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Which year had more males, and how many more males was there than the following year?

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151 000

150 950

150 943

6 533

+7.00

157 476 - 150 943

= 6 533

+50

+6000

157 000

+476

16

Using the inverse to solve problems

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I’m thinking of a number…

I add 104 to it, then I add 73.

​

My answer is 439.

​

What was my original number?

?

?

+104

+73

439

18

I’m thinking of a number…

I add 104 to it, then I add 73.

​

My answer is 439.

​

What was my number?

335

302

-33

-104

439

-40

262

19

I’m thinking of a number…

I add 301 to it, then I add 68.

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My answer is 569.

​

What was my original number?

501

200

-301

-68

569

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Multi step problems

21

Is this a subtraction or an addition problem?

For her party, Jen spent:

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• $15.98 on balloons

• $25.38 on lollies

• $43.72 on a cake

​

Will $80 cover the cost? Explain your reasoning.

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+0.02

$15.98

$16

$85

+0.08

$85.08

+

- 0.38

$25.38

$25

$15.98

$25.38

$43.72

+0.28

$43.72

$44

+

23

How many more babies were born in 2010 than in 2020?

Add these together first

Next add these together

Round and adjust

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+7

155 593

155 600

303 400

-80

303 320

+

+73

147 727

147 800

303 320

Round and adjust

25

+7

150 943

150 950

294 350

+19

294 369

+

-26

143 426

143 400

• 294 369

303 320

Round and adjust

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-20

303 320

303 300

8 900

+ 51

8 951

-

+31

294 369

294 400

• 294 369

303 320

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How many more babies were born in 2019 than in 2010?

Round and adjust

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2019

+24

157 476

157 500

305 900

-68

305 832

+

+44

148 356

148 400

305 832

2010

Round and adjust

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2010

+7

155 593

155 600

303 300

+20

303 320

+

-27

147 727

147 700

• 303 320

305 832

Round and adjust

30

-32

305 832

305 800

2 500

+52

2 552

-

-20

303 320

303 300

• 303 320

305 832

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Pause the video to complete your task

Resume once you’re finished

Independent Worksheet

Now it is your turn to independently use strategies to solve addition and subtraction problems. You will need to open the Worksheet named “Addition and subtraction problems”.

Worksheet Answers

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I’m thinking of a number…

I add 364 to it, then I add 120.

​

My answer is 730.

​

What was my original number?

610

310

-300

-120

730

-10

246

300

-54

Use the round and adjust strategy to solve the problem.

Alfie bought a helmet for $56.55 and a bike for $96.95. How much did it cost altogether?

​

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+0.45

$56.55

$57

$154

-0.50

$153.50

+

+0.05

$96.95

$97

Use the jump strategy to solve the next part of the problem.

If Alfie had $200 to pay for the helmet and the bike, how much change would he receive?

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$170

$164

$163.50

$200

+$6.00

+$0.50

+$30.00

= $164

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