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WS03 - Serving a customer at the market stall

Mathematics, Year 4

By the end of Year 4, students use their understanding of place value to represent tenths and hundredths in decimal form and to multiply natural numbers by multiples of 10. They use mathematical modelling to solve financial and other practical problems, formulating the problem using number sentences, solving the problem choosing efficient strategies and interpreting the results in terms of the situation. Students use their proficiency with addition and multiplication facts to add and subtract, multiply and divide numbers efficiently. They choose rounding and estimation strategies to determine whether results of calculations are reasonable. Students use the properties of odd and even numbers. They recognise equivalent fractions and make connections between fraction and decimal notations. Students count and represent fractions on a number line. They find unknown values in numerical equations involving addition and subtraction. Students follow and create algorithms that generate sets of numbers and identify emerging patterns.

 

They use scaled instruments and appropriate units to measure length, mass, capacity and temperature. Students measure and approximate perimeters and areas. They convert between units of time when solving problems involving duration. Students compare angles relative to a right angle using angle names. They represent and approximate shapes and objects in the environment. Students create and interpret grid references. They identify line and rotational symmetry in plane shapes and create symmetrical patterns. 

 

Students create many-to-one data displays, assess the suitability of displays for representing data and discuss the shape of distributions and variation in data. They use surveys and digital tools to generate categorical or discrete numerical data in statistical investigations and communicate their findings in context. Students order events or the outcomes of chance experiments in terms of likelihood and identify whether events are independent or dependent. They conduct repeated chance experiments and describe the variation in results.

Number

AC9M4N06

develop efficient strategies and use appropriate digital tools for solving problems involving addition and subtraction, and multiplication and division where there is no remainder

Number

AC9M4N08

use mathematical modelling to solve practical problems involving additive and multiplicative situations including financial contexts; formulate the problems using number sentences and choose efficient calculation strategies, using digital tools where appropriate; interpret and communicate solutions in terms of the situation


Annotations

These annotations are interactive and link to a specific timestamp in the video. x
1

Identifies and says the cost of an item.

5 13 1 90
2

Determines and says the amount of change for an item.

14 24 1 90
3

Explains mathematical thinking when calculating change.

25 36 1 90
4

Uses understandings of partitioning, place value and extended number facts to explain the process of calculating the total cost. 

62 74 1 90
5

Identifies the coins that make up an amount.

82 88 1 90
6

Uses a mental calculation strategy to step up the number of cents to the next dollar and the number of dollars to make up to $10.

95 126 1 90
7

Uses a mental strategy to calculate the total amount of change.

127 131 1 90
Transcript

[Teacher] Can I get a pin, please? One of these pins.

 

[Student] That's $2.95

 

[Teacher] $2.95. I actually have $5.

 

[Student] $2.05.

 

[Teacher] Yep sure. Thank you.

 

[Student] Takeaway $2 from $5. And that gives me $3. And then it was only $2.95. So $0.05 less is $2.95. 

 

[Teacher] Thank you, thank you. I was just wondering if I could grab one of these, anklets or bracelets. This one here. And can I also get, one of these key rings just here? Is that okay?

 

[Student] Yep, that’s... that's $6.70.

 

[Teacher] Can you tell me how you worked that out (student’s name)?

 

[Student] I added up $2 to $4, and that got me to $6. And then next I knew that $0.50 plus $0.20. Was, $0.70.

 

[Teacher] Okay, well, I've got $10 to pay for that.

 

[Student] Two one dollars and two $0.05 and one $0.20.

 

[Teacher] Sure, do you know another way that you could work out change? Have you got any other strategies?

 

[Student] ... to, jump to $0.20 so that that would be up to $6.90 and then add $0.10 that will be up to $7 and then add another $2 to get to $9. And then add one more dollar to get to $10. 

 

[Teacher] And what amount do you have in your head?

 

[Student] $3.30.

 

[Teacher] So which method do you think might have been a better method to use, and why? Because one method gave you the answer of $3.30.

 

[Student] Because, I could, get to that number and then add up my coins and, that’s the answer.