Step by step
The question
Question: what comes before 40?
What comes before 40?
We write it in numbers.
The box is the number we want.
= □, 40
1 Find 40
Here is a number line.
2 Go one step left
We land on 39.
3 Write the number
So before 40 comes 39.
= 39, 40
Careful!
Before 0 ones, the ones go back to 9.
The tens go down by 1.
Careful: 40 → 39: the ones go back to 9
4 Check
We check it the other way.
After 39 comes 40.
Yes!
It works.
After 39 comes 40
Let's look back.
First: find 40.
Then: go one step left.
Then: write the number.
Last: check.
Answer
= 39, 40