Number sequence
A number sequence is numbers in order. Counting up goes 1, 2, 3, 4... Each number is one more than the one before.
Key idea
Count on = add 1 each time. Count back = take 1 away each time.
Finding the missing number
Look at the numbers before and after the gap. They help you find what is missing.
Worked example
Fill in: 7, 8, __, 10. After 8 comes 9, and before 10 comes 9. So the missing number is 9.
Remember
- Counting up: numbers get bigger.
- Counting back: numbers get smaller.
- We can also count by 2, 5 or 10.