What is a number pattern?
A number pattern is a list of numbers that follow a rule. The rule tells us how to get from one number to the next — usually by adding, subtracting, or multiplying by the same amount each time.
Key idea / 要点
Find the rule by looking at the gap between two numbers. Then use that rule to continue the pattern.
Finding the next number
Work out what is done at each step, then repeat it. First look at how much the numbers change: if they go up by the same amount, the rule is "add". If they go down, the rule is "subtract". Once you know the rule, you can find any number that comes next.
Worked example / 例题
Look at 5, 10, 15, 20, ?. Each number is 5 more than the one before (10 − 5 = 5). So the rule is "add 5". The next number is 20 + 5 = 25.
Remember / 记住
- Check the gap between numbers first.
- The same rule works for the whole pattern.
- Patterns can go up or down.