In the middle is a number.
On the left goes the number that is ten (or a hundred) less.
On the right goes the number that is ten (or a hundred) more.
The small arrow above the lines shows you the step.
The filled-in example shows the solution.
Example
For parents
What does this exercise practice?
Jumping in steps of 10 and 100 around a number consolidates orientation within the range up to 1000.
Common pitfalls
Do not mix up left and right. Less means backward, more means forward. With steps of 100, only the hundreds digit changes.
How to practice at home
Say a number and work out together ten less, ten more, a hundred less and a hundred more.
Related: Neighbor numbers, Pattern, Number line