The rule is in the roof. It is the same for every floor.
On the left there is a number, on the right you write its result.
Example: the roof shows + 4.
The first floor has the 6. What goes next to it?
6 + 4 = 10, so the 10 belongs next to it.
Tip: count up to the 10 first. From the 6 it is 4 steps to the 10 - exactly the step from the roof.
The number filled in shows the solution.
Example
For parents
What does this exercise practice?
Apply the same rule confidently to several numbers and use the ten as a stepping stone.
Common pitfalls
Some children add up the numbers of the floors. Ask: what does the roof say, and what do you do with it to every number?
How to practice at home
Think up a rule ("always 3 more") and call out numbers to each other in turns. Whoever applies the rule correctly first thinks up the next one.
Related: Number House, Math Caterpillar, Math Problems with a Gap