3.08 Writing expressions using order of operations
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Stories can help us to understand the operations that need to happen, in order to solve a problem. Have a look at this story, to remember how to write a number sentence to represent the story.
Ursula collected sticks at the park and laid them on the ground in $2$2 groups with $2$2 sticks in each group.
John also collected sticks and laid them on the ground in $5$5 groups with $3$3 sticks in each group.
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Which number sentence matches the total number of sticks?
$2+2\times5+3$2+2×5+3
A$2+2+5+3$2+2+5+3
B$2\times2+5\times3$2×2+5×3
C
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This video shows us how the order of operations is used in everyday problems.
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Question 1
Write the number sentence described as:
Multiply $2$2 less than $7$7 with $2$2 less than $9$9.
Question 2
At a self-serve checkout, a couple is sorting their groceries into plastic-free bags. They have a total of $77$77 items and place $7$7 items aside to carry on their own. The remaining $70$70 items are evenly separated into their bags, with $14$14 items in each bag.
Which number sentence describes the amount of bags and items they have to carry?
$70\div14+7$70÷14+7
A$70\times14+7$70×14+7
B$70+14\div7$70+14÷7
C$70+14\times7$70+14×7
D
The order of operations:
- Solve anything inside grouping symbols (brackets).
- Solve any multiplication or division, including powers, working from left to right.
- Solve any addition or subtraction, working from left to right.