Step by step
The question
Question: what comes next?
30, 27, 24, 21, □.
30, 27, 24, 21, □
1 Find the jumps
2 Find the rule
Every jump is the same: −3.
The rule is: take away 3 each time.
= Rule: take away 3 each time
3 Use the rule
The number before the box is 21.
21 − 3 = 18.
21 − 3 = 18
So the next number is 18.
= 30, 27, 24, 21, 18
4 Check
We go one jump back.
18 + 3 is 21.
Yes!
It works.
18 + 3 = 21
Let's look back.
First: find the jumps.
Then: find the rule.
Then: use the rule.
Last: check.
Answer
= 30, 27, 24, 21, 18