Step by step
The question
Question: what comes after 19?
What comes after 19?
We write it in numbers.
The box is the number we want.
= 19, □
1 Find 19
Here is a number line.
2 Go one step right
We land on 20.
3 Write the number
So after 19 comes 20.
= 19, 20
Careful!
After 9 ones, the ones start again at 0.
The tens go up by 1.
Careful: 19 → 20: the ones start again at 0
4 Check
We check it the other way.
Before 20 comes 19.
Yes!
It works.
Before 20 comes 19
Let's look back.
First: find 19.
Then: go one step right.
Then: write the number.
Last: check.
Answer
= 19, 20