Finding Missing Numbers
Sometimes a number is missing from a sequence. We can use the numbers around the empty space to find the missing number.
Looking carefully at the order or pattern helps us find the answer.
Learning Objectives
- Find missing numbers in simple sequences.
- Use counting to find a missing number.
- Recognise simple number patterns.
- Check whether the missing number is correct.
Missing Numbers in Counting
When numbers are counted in order, we can use the numbers before and after a missing number to find it.
The missing number is 3.
We know this because 3 comes after 2 and before 4.
Finding the Next Number
Sometimes we need to find what comes next in a sequence. We can look at how the numbers are changing.
The missing number is 9.
Simple Number Patterns
A pattern is an arrangement that follows a rule. Some simple number patterns increase by the same amount.
The pattern increases by 2 each time, so the missing number is 10.
We should look at the numbers carefully before deciding what the rule of the pattern is.
Checking the Answer
After finding a missing number, check the whole sequence again. The answer should fit correctly with the numbers before and after it.
Every number is one more than the previous number, so the sequence follows the same rule.
Common Mistakes
- Do not guess the missing number without checking the sequence.
- Look at both sides of the missing space when possible.
- Check whether the numbers follow the same pattern.
Practice
1. Find the missing number: 1, 2, __, 4.
2. Find the missing number: 6, 7, __, 9.
3. Find the missing number: 10, __, 12.
4. What comes next: 2, 4, 6, __?
Try It Yourself
Write three number sequences with one missing number. Give them to someone else and ask them to find the missing numbers.
Quick Revision
- Missing numbers can be found by looking at nearby numbers.
- Counting helps us find missing numbers.
- Patterns can help us find missing numbers.
- Always check that the answer fits the sequence.
Next Step
Finding missing numbers helps us think carefully about patterns. In the next lesson, you will use clues to solve simple logical problems.