Register Login
Evulpo Logo

Benefit from a yearly subscription now!

Save 44%

£11.99 / Month

£6.67 / Month

Chapter overview

Maths

Number and place value

Addition and subtraction

Multiplication and division

Fractions

Measurement

Geometry - properties of shapes

Geometry - position and direction

Statistics

Ratio and proportion

Algebra

Maths

Missing number problems

Your lesson progress
 
 
0%

Summary

Download

Missing number problems

​​In a nutshell

Expressions involving an unknown number are needed to solve missing number problems. Unknown numbers are usually represented by letters.


Example 1

x+10=12x + 10 = 12

This is the same as asking: "what is added to 1010​ to get 1212​?"


The answer is x=2x=2


Note: xx is the letter commonly used for an unknown.



Method for solving

​​Procedure

1.
Write out an equation 
2.
Work out the value of the unknown
​
Example 2


Anna has £20£20​. She shares £5£5​ with her brother and uses £12£12​ to buy a new dress. how much money does she have left?

​

Write an expression:


5+12+x=205 + 12 + x = 20

Solve for xx:

​x=3x= 3​


Anna has £3‾\underline{£3}​ remaining.

Frequently Asked Questions (FAQ)

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

© 2020 – 2023 evulpo AG

Your data protection

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners who may combine it with other information that you’ve provided them or that they’ve collected from your use of their services. By clicking on either "Accept cookies" or "Necessary cookies only", you agree to this (read more in our Privacy Policy). Privacy Policy