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Chapter overview
Learning goals
Learning Goals
Maths
Summary
Expressions involving an unknown number are needed to solve missing number problems. Unknown numbers are usually represented by letters.
$x + 10 = 12$
This is the same as asking: "what is added to $10$ to get $12$?"
The answer is $x=2$
Note: $x$ is the letter commonly used for an unknown.
1. | Write out an equation |
2. | Work out the value of the unknown |
Example 2Anna has $£20$. She shares $£5$ with her brother and uses $£12$ to buy a new dress. how much money does she have left? Write an expression:
Solve for $x$: $x= 3$ Anna has $\underline{£3}$ remaining. |
Expressions involving an unknown number are needed to solve missing number problems. Unknown numbers are usually represented by letters.
$x + 10 = 12$
This is the same as asking: "what is added to $10$ to get $12$?"
The answer is $x=2$
Note: $x$ is the letter commonly used for an unknown.
1. | Write out an equation |
2. | Work out the value of the unknown |
Example 2Anna has $£20$. She shares $£5$ with her brother and uses $£12$ to buy a new dress. how much money does she have left? Write an expression:
Solve for $x$: $x= 3$ Anna has $\underline{£3}$ remaining. |
FAQs
Question: How do I solve a missing number problem?
Answer: Use trial and error to try out possible solutions.
Question: What do letters mean in an unknown number problem?
Answer: Unknown numbers are usually represented by letters.
Theory
Exercises
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