In each row there are three boxes next to each other.
On the left goes the number that is one step less.
On the right goes the number that is one step more.
Example: 50 is in the middle, the step is 9.
Left: 50 − 9 = 41. Right: 50 + 9 = 59.
Tip: work with 10 first, then go back 1 -- 50 − 10 = 40, and 40 + 1 = 41.
The numbers filled in show the solution.
Example
For parents
What does this exercise practice?
Calculate in equal steps around a number, using the trick with the tens.
Common pitfalls
Do not mix up left and right. Less means backward, more means forward.
How to practice at home
Name a number and work out nine less and nine more together, for example on the hundred chart.
Related: Neighbor Numbers, Number Line